Rehmannia glutinosa.

Herbs & Botanicals · Herbs · A Chinese root used raw and prepared, mostly studied in formulas

Rehmannia (Di Huang)

Q: What is rehmannia?

Rehmannia glutinosa is a Chinese plant whose root is a major herb in Chinese medicine. It is used raw (sheng di huang) or steamed and prepared (shu di huang). Most research is on multi-herb formulas that contain it.

Q: What is the difference between raw and prepared rehmannia?

They are the same plant but different products. Steaming or wine-processing changes the chemistry: iridoid glycosides fall and other compounds rise. In mice, raw root reduced clotting more and prepared root improved blood counts more. Do not assume results for one apply to the other.

Q: Does rehmannia help diabetic kidney disease?

Meta-analyses of Chinese trials report lower urine albumin when formulas such as Liuwei Dihuang are added to standard care, but the trials are low quality. One Hong Kong trial found slower decline in kidney filtering and no significant change in urine albumin. No trial tests rehmannia alone.

Q: What is Liu Wei Di Huang Wan?

It is a six-herb Chinese formula led by prepared rehmannia. Studies of it are studies of the combination, so the effect cannot be credited to rehmannia alone.

Q: What is catalpol?

Catalpol is a compound in the root that is the focus of drug-like research. It has been studied in animals for diabetes and nerve protection, and in rats for how it is absorbed and cleared. No human trial of catalpol was found.

Q: Does it lower blood sugar?

Add-on trials of Liuwei Dihuang with diabetes drugs report small glucose improvements, but quality is low and HbA1c results disagree. Animal studies of catalpol report lower sugar. If you take diabetes medicines, talk to your prescriber first.

Q: Is there evidence for arthritis, osteoporosis or anemia?

For rheumatoid arthritis no trial was found. For osteoporosis, one small trial found a rehmannia decoction similar to alendronate, with no placebo. For anemia, a Si Wu Tang analysis showed no difference from placebo in anemia markers, and a monograph rates adjunct use in aplastic anemia as preliminary.

Q: What are the side effects?

Reference pages list diarrhea and abdominal bloating, and stomach upset or dizziness. Trials of formulas report mostly mild events, though reporting was incomplete. Rehmannia alone has not been tested in safety trials.

Q: Does it interact with medicines?

Interactions are mostly theoretical. One database lists immunosuppressants, diuretics and steroids without a mechanism. Extra blood-sugar lowering with diabetes drugs is possible. Mouse work suggests raw root may reduce clotting. No human interaction study was found, so tell your doctor or pharmacist.

Q: Is it safe in pregnancy or breastfeeding, or for children?

Not established. Reference pages say information is insufficient or unavailable, and a monograph says no safe or effective amount is known for children.

Rehmannia glutinosa (Gaertn.) Libosch. ex Fisch. & C.A.Mey. · also called Rehmannia, Chinese foxglove, di huang, sheng di huang (raw), shu di huang (prepared); rehmannia (Spanish)

Rehmannia is the root of a Chinese plant. It is used raw (sheng di huang) or steamed (shu di huang). Almost all human trials tested multi-herb formulas such as Liu Wei Di Huang Wan, so rehmannia alone is not shown to work. Pooled low-quality trials report benefits in diabetic kidney disease and other uses; arthritis and diabetic neuropathy have no trial. Reference pages list diarrhea and bloating, and pregnancy data are missing. Ask a doctor or pharmacist about amounts and medicines.

General information, not medical advice. Last substantive update October 25, 2026 · Not medically reviewed. A named clinician has not signed off on this page. How this page is made

About Rehmannia (Di Huang)

Rehmannia glutinosa root is a core herb of Chinese medicine, used raw (sheng di huang) or steamed and prepared (shu di huang). Nearly all human research tested multi-herb formulas, mainly Liuwei Dihuang, Zhibai Dihuang and Si Wu Tang, so rehmannia's own effect is not known. Meta-analyses of mostly low-quality Chinese trials report benefits in diabetic kidney disease, lupus steroid reduction and menopause-like symptoms after breast cancer; for arthritis, anemia and diabetic nerve damage no trial was found, and osteoporosis rests on one small trial. Catalpol, a compound in the root, is studied like a drug in animals. Reference pages list diarrhea and bloating; interactions with medicines are theoretical; pregnancy and breastfeeding data are missing. EMA, NCCIH and LiverTox entries were not found. Ask a doctor or pharmacist about amounts.

What it is

Rehmannia glutinosa (family Rehmanniaceae) is a plant from China. The root is the part used. GBIF treats the older name with authority (Gaertn.) DC. as a synonym.

Raw root (sheng di huang) and prepared root (shu di huang) are used differently in Chinese medicine. Steaming or wine-processing changes the compounds and effects.

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Raw root, prepared root, catalpol and formulas

Raw and prepared root are different products. Catalpol is one compound of the root and is studied in animals; a review says it cannot stand for the whole root.

Formulas such as Liuwei Dihuang (six herbs), Zhibai Dihuang and Si Wu Tang (four herbs) are combinations. In this page they are always labelled as such.

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What the research shows

Pooled Chinese trials report lower urine albumin in diabetic kidney disease and larger steroid reduction in lupus when a formula is added. A Hong Kong trial found slower kidney decline. Most trials were not blinded and had low quality ratings.

No controlled trial was found for rheumatoid arthritis or diabetic neuropathy. Osteoporosis rests on one small trial against alendronate. A Si Wu Tang analysis showed no difference in anemia markers.

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At a glance

Traditional uses history, not proof

Chinese medicine: raw root to clear heat and cool blood; prepared root to nourish yin and blood
Lead herb in Liuwei Dihuang, Zhibai Dihuang and Si Wu Tang
Used for kidney, bone, menstrual and blood complaints in traditional teaching

Studied for research

Diabetic kidney disease, low certainty (formulas)
Type 2 diabetes blood sugar, very low certainty (formulas)
Lupus steroid reduction, low certainty (Zhibai Dihuang)
Osteoporosis, very low (one small trial)
Arthritis and diabetic neuropathy, insufficient (no trial found)

Main compounds

Catalpol and other iridoid glycosides
Acteoside (verbascoside)
Rehmannioside D
Polysaccharides; furfural compounds rise on processing

Common forms

Raw or dried root (sheng di huang)
Steamed or wine-processed root (shu di huang)
Decoction, pills or granules of formulas (combinations)
Leaf extract (tested once for acne; a different product)
Results from one form should not be assumed for another

Research links: Liuwei Dihuang in early diabetic nephropathy, meta-analysis (2026) · Rehmannia-6 granules in diabetes and CKD, RCT (2023) · Systematic review of Radix Rehmanniae (2022) · Restorative Medicine monograph on rehmannia · Research Library · Genes & Biomarkers Library

The plant and its history

Accepted scientific name: Rehmannia glutinosa (Gaertn.) Libosch. ex Fisch. & C.A.Mey.
Naming authority: (Gaertn.) Libosch. ex Fisch. & C.A.Mey.; GBIF lists "Rehmannia glutinosa (Gaertn.) DC." as a synonym of this accepted name
Synonyms: Rehmannia glutinosa (Gaertn.) DC.; Rehmannia glutinosa (Gaertn.) Steud.
Common names: Rehmannia (English); Chinese foxglove (English); Di huang / dihuang (Chinese (pinyin)); Sheng di huang (raw/dried root) (Chinese (pinyin)); Shu di huang (steamed/prepared root) (Chinese (pinyin)); Rehmanniae radix (Latin pharmacopoeial)
Botanical family: Rehmanniaceae per GBIF. A 2023 review abstract still names Scrophulariaceae, which appears to be an older grouping (not verified).
Classification: Plantae > Lamiales > Rehmanniaceae > Rehmannia > Rehmannia glutinosa
Native range: Not verified from a primary source read; reviews describe it as a Chinese medicinal root.
Habitat: Not verified.
What the plant looks like: Roots: The tuber root is the part used (2022 review).; Stems: Not verified.; Leaves: Leaf extract was tested once for acne.; Flowers: Not verified.; Fruit: Not verified.
Cultivation: Not verified from a source read.
Harvest and processing: Two main processed forms: dried (raw) root (sheng di huang, "Dry Radix Rehmanniae") and processed root "Radix Rehmanniae Praeparata" (shu di huang), steamed or rice-wine processed over repeated cycles; processing changes taste, property, chemistry and effects (2022 review; mouse study used nine cycles of rice-wine processing).
Look-alikes and adulterants: Name: Rehmannia chingii and other Rehmannia species; Note: A 2025 Nature Communications genome paper deals with Rehmannia chingii; it was not read. Species mix-up risk is not documented in the sources read.; Name: Foxglove (Digitalis); Note: Rehmannia is nicknamed Chinese foxglove but is a different plant. We did not research whether it shares heart-active compounds with foxglove; NOT verified.
Sustainability and conservation: Not assessed in the sources read.

Traditional use and history history, not clinical proof

Tradition or era	Documented use	Source
Traditional Chinese medicine	The 2022 review says the root was first recorded in Shennong's Classic of Materia Medica, and lists traditional effects such as clearing heat, cooling blood, stopping bleeding, nourishing yin and blood and filling marrow.	p34767834
Raw (sheng di huang) vs prepared (shu di huang)	Dried root and processed root are used for different clinical purposes, and the 2019 mouse study calls this a classic case of processing changing a herb. In the 2022 review, raw and processed root differ in property, taste, efficacy, chemistry and pharmacology.	p30359761
Formulas	Rehmannia is the lead herb in Liuwei Dihuang (Liu Wei Di Huang Wan, six herbs), Zhibai Dihuang and Siwu (Si Wu Tang, four herbs) formulas, per the 2023 review and trials.	p37907043
Pharmacopoeias and regulators	Listed in the Pharmacopoeia of the PRC; no EMA/HMPC monograph, NCCIH page or Commission E monograph found.	s-restorativemedicine-rehmannia

Traditional use shows how a plant was used. It does not show that a supplement works or is safe today.

What is inside, and how it may work

What the plant contains and how those compounds act in cells and animals. Laboratory and animal mechanisms are not proven effects in people.

Main compounds

Compound	Family	Where it is concentrated	Activity studied	Level of evidence
Catalpol PubChem 91520	iridoid glycoside	Root (more in raw than in processed root per mouse-study chemistry: iridoid glycosides decrease with processing) A pesticide-removal paper measured about 0.25 mg/mL catalpol in its test extract; no market content data.	The most studied single compound ("drug-like research"): animal models report lower blood sugar, anti-inflammatory and nerve-protective effects; a version was developed as a stroke drug candidate (rat PK paper). No human trial found. ^{1 7 33 8}	Animal research
Aucubin PubChem 91458	iridoid glycoside	Root	Listed among iridoid glycosides in the 2023 review; no human data. ¹³	Animal research
Ajugol PubChem 6325127	iridoid glycoside	Root	Supposed active component with catalpol and acteoside for bone effects (2017 review); no human data. ²⁰	Animal research
Acteoside (verbascoside) PubChem 5281800	phenylpropanoid glycoside	Root	Supposed active component (2017 review); no human data. ^{20 13}	Animal research
Rehmannioside D PubChem 92044472	iridoid glycoside (rehmannioside)	Root, especially prepared root	Named in the 2022 review as a component needing further study; no human data. ¹⁷	Animal research
Polysaccharides and furfural derivatives	sugars; processing products	Root; furfural compounds increase on processing	Iridoid glycosides decreased and furfural derivatives increased after nine cycles of rice-wine processing in one analysis. ^{8 13}	Laboratory research

Mechanisms, receptors and pathways

Target or pathway	Gene or receptor	What was found	Level
Blood sugar and diabetes complication pathways (AMPK/PI3K/Akt, NF-kB, AGE/RAGE)	Not studied in humans	Catalpol in animal models inhibits inflammation, oxidative stress and cell death through several signalling pathways. ¹	Animal research
Bone cells	Not studied in humans	A review reports the root balances bone-forming and bone-breaking cells in osteoporosis models. ²⁰	Animal research
Clotting and blood-cell production	Not studied in humans	In mice, raw root extract reduced clotting more than processed root, and processed root improved blood counts more. ⁸	Animal research
Brain-related genes (computer prediction)	Exploratory	A 2026 review used network pharmacology to link Liuwei Dihuang compounds to neurodegeneration-related genes; the authors call this exploratory. ¹¹	In silico

Absorption, metabolism and elimination

Absorption: Rats: radiolabelled catalpol was rapidly absorbed (median Tmax 0.75 h; plasma half-life of total radioactivity about 1.52 h).
Distribution: Rats: highest in stomach, large intestine, bladder and kidney.
Metabolism: Rats: parent catalpol was the main plasma and urine compound; gut bacteria and beta-glucosidase made two metabolites.
Elimination: Rats: 94.82% recovered over 168 h, about 57.5% in urine and 37.3% in faeces.
Bioavailability: Not established in humans.

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Isolated compounds versus whole extracts

Three different things are studied. (1) The raw (dried) root. (2) The prepared (steamed or wine-processed) root, which has less iridoid glycoside and more furfural-type compounds and different effects in mice. (3) Single compounds, mainly catalpol, studied mostly in animals. Human research is almost all on multi-herb formulas (Liuwei Dihuang, Zhibai Dihuang, Si Wu Tang). A 2022 review says catalpol cannot stand for the whole root.

Nutritional composition

No food-composition data for the root were read; it is used as a medicine, not a food.

14benefits and uses looked at

33studies and sources checked

Low certaintybest evidence rating found

8lab markers tracked in trials

4 low certainty6 very low certainty4 not enough evidence

What is Rehmannia (Di Huang) good for?

The main proposed uses and how strong the human evidence is for each. Most are for formulas, not rehmannia alone.

Diabetic kidney disease: Liuwei Dihuang-type formula added to standard care (combination)Low certaintyMeta-analyses of Chinese trials (2016, 2018, 2023, 2026) report lower urine albumin and better kidney blood tests when a rehmannia-containing formula is added. The 2026 review of 11 trials rates the overall evidence quality as low. Rehmannia alone is not tested. Diabetes with kidney disease: one multicentre trial of Rehmannia-6-based granules (combination)Low certaintyIn 148 adults over 48 weeks, kidney filtering fell 2.7 ml/min per year less than with standard care alone (95% CI 0.1 to 5.3); urine albumin did not change significantly. Patients were not blinded. Type 2 diabetes: blood sugar with Liuwei Dihuang pills added to medicines (combination)Very low certaintyTwo meta-analyses report better fasting and after-meal glucose; they disagree on HbA1c. Trial quality was low. Diabetic eye disease: herbal combinations that often include rehmanniaVery low certaintyA 2023 review of 18 trials found better outcomes with mixed herbal combinations (69 herbs). Rehmannia was only one of the most-used herbs. Diabetic nerve damage (neuropathy)Not enough evidenceNo randomized trial was found. A 2011 review says there are few studies of the formula as a whole. Memory and thinking problems: Liuwei Dihuang added to usual care (combination)Very low certaintyA 2026 review of 12 trials (1,137 people) found a 2.34-point higher MMSE score; authors call the evidence weak and varied. Rehmannia root on its ownNot enough evidenceNo controlled trial of the plain root was found. A review of 30 Korean papers draws a stronger conclusion than its abstract supports. Menopause-like symptoms after breast cancer treatment (rehmannia-led formulas)Very low certaintyA 2025 meta-analysis of 17 trials (1,139 patients) found lower symptom scores than with Western medicine; the authors note flaws and high variation. Lupus: Zhibai Dihuang pill added to steroids (combination)Low certaintyTwenty trials (1,470 patients) report larger steroid dose reduction with the added formula; a small astragalus-rehmannia trial had mixed results. Evidence is preliminary. Bone loss (osteoporosis): Dihuang decoction versus alendronateVery low certaintyOne 72-person trial found similar bone-density gains with the decoction and alendronate; no placebo group. A review calls the wider trial pool poorly designed. Rheumatoid arthritisNot enough evidenceNo controlled human trial was found. Anemia and "nourishing blood"Not enough evidenceA monograph grades adjunct use in aplastic anemia as C (preliminary). A Si Wu Tang analysis found no difference from placebo in anemia markers. Mouse work favours prepared root for blood counts. Period pain: Siwu-family formulas (combination)Low certaintyA 2020 review of five trials favoured a modified formula over NSAIDs; a pilot placebo trial of plain Si Wu Tang was not significant at the end of treatment. Acne: a rehmannia leaf extract (not the root)Very low certaintyA 22-woman proof-of-concept trial; the placebo group also improved.

Benefits, one by one

Each card is a research question, not a promise. Tap a goal to filter. Open a card to see the studies, doses and limits.

Diabetic kidney disease: Liuwei Dihuang-type formulas added to standard care (combination)

Low certainty

Several reviews pool Chinese trials in which a rehmannia-containing formula was added to standard diabetes and kidney care. They report less urine albumin and better kidney blood tests. The trials are mostly low quality, and the formula holds six or more herbs, so this does not show what rehmannia does by itself.

4 studiesFormula (combination product): rehmannia is mixed with other herbs, s…

Studies, doses and limits

What the trials found

A 2026 meta-analysis of 11 randomized trials (1,007 patients) found lower urinary albumin excretion, creatinine and urea nitrogen when Liuwei Dihuang was added. A 2016 meta-analysis of 18 trials (1,275 patients) and a 2018 meta-analysis of 14 studies found similar results. A 2023 network meta-analysis of 41 trials (3,562 patients) ranked Zhibai Dihuang and Liuwei Dihuang highest for lowering urinary albumin. The authors of the 2026 review rate the overall evidence quality as low.

Results

Lower urine albumin, creatinine and urea nitrogen compared with standard care alone, in low-quality Chinese trials.

Effect sizes as reported

2026 review: urinary albumin excretion MD -37.30 (95% CI -47.51 to -27.09, I2 93%); creatinine MD -5.96 (-9.27 to -2.65); urea nitrogen MD -0.91 (-1.46 to -0.36). 2018 review: overall efficacy OR 2.87 (1.98 to 4.15).

Why this rating

The reviews agree in direction, but the trials were not blinded, had no allocation concealment, and varied a lot (I2 93%). The 2026 authors call the evidence quality low; publication bias cannot be excluded.

Form and dose studied

Formula (combination product): rehmannia is mixed with other herbs, so any effect cannot be credited to rehmannia alone. No amounts are given here. Ask a doctor or pharmacist.

Who was studied

Adults with early diabetic kidney disease, nearly all in China.

Limits

No trial tests rehmannia alone. Formula contents differ between trials. Reports are mostly from China, and trials in other regions are lacking. Only adverse events in 6 of 11 trials were reported in the 2026 review.

Why researchers looked

Diabetic kidney disease is a common cause of kidney failure, and Liuwei Dihuang (Liu Wei Di Huang Wan) is described by one trial team as the most used Chinese medicine formula type.

Traditional use

In Chinese medicine, prepared rehmannia root (shu di huang) is the lead herb in kidney-nourishing formulas such as Liuwei Dihuang and Zhibai Dihuang. This is traditional use, not proof of benefit.

Proposed mechanism Animal research

Lab and animal work on catalpol and other root compounds proposes anti-inflammatory and antioxidant effects on the kidney. No human mechanism has been shown.

A proposed mechanism does not show that the effect happens in people.

Adverse events were reported in 12 of 287 formula patients and 12 of 277 controls in the trials that reported them (2026 review), mostly mild; reporting was incomplete.

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Type 2 diabetes with chronic kidney disease: one multicentre trial of Rehmannia-6-based granules (combination)

Low certainty

One well-run trial in Hong Kong gave patients rehmannia-based granules on top of standard care for 48 weeks. Kidney filtering (eGFR) fell more slowly, but urine albumin did not change significantly. The granules were individualised mixtures, so this is again a combination, not rehmannia alone.

1 studiesGranule formulas based on Rehmannia-6, individualised by the practiti…

Studies, doses and limits

What the trials found

In the SCHEMATIC trial (n=148, adults with type 2 diabetes, eGFR 30 to 90 and severely raised albuminuria), assessors were blinded but patients were not. After 48 weeks eGFR fell 2.0 per year with add-on Chinese medicine versus 4.7 with standard care alone. The UACR difference was not significant. Eighty-five adverse events occurred in 50 participants (31% add-on vs 36% control).

Results

Slower eGFR decline; no significant change in urine albumin ratio.

Effect sizes as reported

eGFR difference 2.7 ml/min/1.73 m2 per year (95% CI 0.1 to 5.3, P=0.04); UACR ratio 0.89 (0.72 to 1.10, P=0.28).

Why this rating

One trial, open to bias because patients were not blinded and there was no placebo; the lower end of the confidence interval is barely above zero; individualised multi-herb formulas. Some authors report ties to drug companies.

Form and dose studied

Granule formulas based on Rehmannia-6, individualised by the practitioner (combination).

Who was studied

148 adults, Hong Kong, stage 2-3 CKD with type 2 diabetes.

Limits

Single regional trial; no placebo; formula varied between patients; 48 weeks only.

Why researchers looked

Researchers tested whether a protocol of Rehmannia-6-based Chinese medicine, the most used formula type, slows kidney decline in real-world patients.

Traditional use

Liuwei Dihuang-type formulas have been used for kidney complaints in Chinese medicine for a long time.

Proposed mechanism Pharmacological theory

Not tested in the trial.

A proposed mechanism does not show that the effect happens in people.

Adverse events were similar between groups in this trial.

Type 2 diabetes: blood sugar with Liuwei Dihuang pills added to medicines (combination)

Very low certainty

Two meta-analyses of Chinese trials say adding Liuwei Dihuang pills to diabetes medicines improved fasting and after-meal glucose. They disagree on HbA1c (the three-month average). Study quality was low and rehmannia was never tested alone.

4 studiesFormula (combination product): rehmannia is mixed with other herbs, s…

Studies, doses and limits

What the trials found

A 2013 meta-analysis of 18 studies (1,609 patients) found better fasting glucose, 2-hour glucose and HbA1c with the pills added. A 2016 meta-analysis of 18 studies (1,275 patients with diabetic nephropathy) found better fasting and after-meal glucose but no significant HbA1c change. Authors of both call study quality low or less adequate.

Results

Small glucose improvements in low-quality add-on trials; HbA1c inconsistent.

Effect sizes as reported

2013 review: fasting glucose MD 0.54 mmol/L (0.15 to 0.93), 2-hour glucose 1.05 (0.29 to 1.81), HbA1c 0.23 (0.02 to 0.45). 2016 review: fasting glucose MD -0.36 (-0.46 to -0.25), HbA1c MD -0.14 (-0.49 to 0.21, P=0.43). Signs of the differences are as printed in the abstracts.

Why this rating

Low-quality trials, inconsistent HbA1c result, formula not rehmannia alone, and abstracts do not state a bias rating.

Form and dose studied

Formula (combination product): rehmannia is mixed with other herbs, so any effect cannot be credited to rehmannia alone.

Who was studied

Adults with type 2 diabetes in China.

Limits

No placebo-controlled trial of rehmannia root alone was found.

Why researchers looked

Liuwei Dihuang is widely used with diabetes drugs in China, so reviewers pooled the trials.

Traditional use

Rehmannia-based formulas are used with diabetes medicines in China; the traditional basis is not described in the sources we read.

Proposed mechanism Animal research

Animal studies of catalpol and other root compounds report lower blood sugar; not shown in humans.

A proposed mechanism does not show that the effect happens in people.

Adding anything that lowers blood sugar to diabetes medicines can matter; see the safety page.

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Diabetic eye disease (proliferative retinopathy): herbal combinations that often include rehmannia

Very low certainty

A 2023 meta-analysis of 18 trials found better outcomes when herbal combinations were added to eye treatment. Rehmannia was one of the four most-used herbs among 69 herbs. Nothing here isolates rehmannia.

1 studiesMixed herbal combinations.

Studies, doses and limits

What the trials found

The 2023 meta-analysis (18 trials, 1,392 patients) found a higher effective rate, better visual acuity and more regression of new vessels than controls. The herbs varied across trials.

Results

Better effective rate and vision; many different herb mixtures.

Effect sizes as reported

Effective rate OR 2.99 (95% CI 2.18 to 4.10); visual acuity MD 0.10 (0.06 to 0.13).

Why this rating

69 different herbs across trials, few trials, some outcomes with very high variation (I2 up to 95.6%). Not a rehmannia product.

Form and dose studied

Mixed herbal combinations.

Who was studied

People with proliferative diabetic retinopathy, mostly Chinese trials.

Limits

Rehmannia is not isolated; safety was not well explored (authors).

Why researchers looked

Diabetic retinopathy is a leading cause of vision loss and herbs are used alongside eye treatments in China.

Traditional use

Traditional formulas for the eyes often include rehmannia.

Proposed mechanism Pharmacological theory

None tested.

A proposed mechanism does not show that the effect happens in people.

Authors say safety needs to be studied.

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Diabetic nerve damage (neuropathy): no human trial found

Not enough evidence

Reviews mention that rehmannia-based formulas may help diabetic neuropathy, based on small studies and lab work. We did not find a randomized trial of rehmannia, or of a rehmannia formula, for diabetic peripheral neuropathy.

2 studiesNot applicable

Studies, doses and limits

What the trials found

The 2011 review says the Rehmannia Six formula appears to have beneficial effects on blood glucose, neuropathy and nephropathy but notes there are few studies of the formula as a whole. Our PubMed search for a randomized trial or meta-analysis for diabetic peripheral neuropathy returned none.

Results

No controlled human data found.

Effect sizes as reported

None.

Why this rating

No randomized human trial found; review statements rest on lab and small studies.

Form and dose studied

Not applicable

Who was studied

Not applicable.

Limits

Evidence gap.

Why researchers looked

Neuropathy is a common diabetic complication and a rehmannia formula review lists it.

Traditional use

Traditional formula use only.

Proposed mechanism Animal research

Animal work on catalpol and root compounds proposes nerve protection; no human proof.

A proposed mechanism does not show that the effect happens in people.

Not applicable.

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Memory and thinking problems: Liuwei Dihuang added to usual care (combination)

Very low certainty

A 2026 meta-analysis of 12 trials (1,137 people) found higher memory-test scores when Liuwei Dihuang was added to usual care. The authors warn that the trials were weak and varied.

1 studiesFormula (combination product): rehmannia is mixed with other herbs, s…

Studies, doses and limits

What the trials found

Liuwei Dihuang plus conventional therapy gave a higher Mini-Mental State Examination score than conventional therapy alone. Fewer adverse events were reported in the formula group but reporting was limited.

Results

About 2 more points on a 30-point memory screen, in weak trials.

Effect sizes as reported

MMSE MD 2.34 (95% CI 0.88 to 3.79).

Why this rating

Unclear randomization and blinding, large variation, overall risk of bias judged 'some concerns' by the authors.

Form and dose studied

Formula (combination product): rehmannia is mixed with other herbs, so any effect cannot be credited to rehmannia alone.

Who was studied

People with dementia or other cognitive disorders; mainly Asian trials.

Limits

Weak trials; whether a 2-point difference matters to patients is not shown by the abstract.

Why researchers looked

Liuwei Dihuang is widely used in Asia for age-related cognitive decline.

Traditional use

Kidney-tonic formulas are traditionally used for memory loss in older people; traditional use only.

Proposed mechanism Pharmacological theory

The review used computer prediction to link formula compounds to brain-related genes. This is an exploratory in silico step, not human proof.

A proposed mechanism does not show that the effect happens in people.

Fewer adverse events with the formula, reporting was limited.

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Rehmannia root on its own: what human evidence exists

Not enough evidence

Almost no controlled human trial tests plain rehmannia root. A review of 30 Korean papers says the root is effective for inflammatory and metabolic diseases, but its conclusion is stronger than its data. Animal and lab work on the root is plentiful; human proof is not.

3 studiesRaw and prepared root are chemically different and should not be assu…

Studies, doses and limits

What the trials found

The 2017 Korean literature review pooled 30 publications (antioxidant effects, blood glucose, autonomic nerve effects, effects on the body) and concluded effectiveness; the abstract does not show controlled-trial data. The 2022 systematic review says catalpol results cannot stand for the whole root and the pharmacology of raw and prepared root differs.

Results

No clear controlled human outcome for the root alone.

Effect sizes as reported

None.

Why this rating

No randomized trial of rehmannia root alone was found; the favourable review conclusion is not backed by controlled data in its abstract.

Form and dose studied

Raw and prepared root are chemically different and should not be assumed to act alike.

Who was studied

Unclear.

Limits

Evidence gap: root alone, raw versus prepared, never compared in humans.

Why researchers looked

The root is a staple of Chinese and Korean medicine, so reviewers looked for single-herb evidence.

Traditional use

Raw (sheng di huang) and prepared (shu di huang) root are used for different purposes in Chinese medicine; see the science tab.

Proposed mechanism Animal research

Lab studies report anti-inflammatory and blood-sugar effects of catalpol and other compounds.

A proposed mechanism does not show that the effect happens in people.

Not applicable.

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Menopause-like symptoms after breast cancer treatment (formulas led by rehmannia)

Very low certainty

A 2025 meta-analysis of 17 Chinese trials found lower symptom scores with rehmannia-led herbal formulas than with Western medicine. The trials had flaws and varied a lot. The formulas contained other herbs.

1 studiesFormula (combination product): rehmannia is mixed with other herbs, s…

Studies, doses and limits

What the trials found

17 randomized trials (1,139 patients). Kupperman index fell more with the herbal formulas than with Western medicine. Performance status improved. Quality of life (FACT-B) and gonadal hormones did not differ. No severe adverse reactions were reported.

Results

Lower symptom score; no difference in quality of life or hormones.

Effect sizes as reported

Kupperman index MD -12.79 (p<0.01).

Why this rating

The authors warn of methodological flaws and high variation; the comparator was Western medicine, not placebo; formulas had other herbs.

Form and dose studied

Formula (combination product): rehmannia is mixed with other herbs, so any effect cannot be credited to rehmannia alone.

Who was studied

Breast cancer patients with perimenopausal syndrome, China.

Limits

Mixed formulas; comparator not placebo; possible effects on cancer treatment are not addressed in the abstract.

Why researchers looked

Hot flushes and other symptoms are common after breast cancer treatment and hormone therapy is often not an option.

Traditional use

Rehmannia is traditionally the main herb in yin-nourishing formulas for menopause-like symptoms.

Proposed mechanism Preliminary mechanism

Not shown in humans. T-cell percentages changed in the pooled trials (CD4 up, CD8 down) but this is a lab marker.

A proposed mechanism does not show that the effect happens in people.

Breast cancer patients should talk to the cancer team before using herbal formulas.

¹⁵

Lupus: Zhibai Dihuang pill and astragalus-rehmannia pair added to steroids (combination)

Low certainty

A 2020 review of 20 trials found people with lupus needed a larger reduction in steroid dose when a rehmannia-based formula (Zhibai Dihuang) was added. A small 2014 trial of an astragalus plus rehmannia pair in lupus kidney disease had mixed results. Both are combinations and the evidence is preliminary.

2 studiesFormula (combination product): rehmannia is mixed with other herbs, s…

Studies, doses and limits

What the trials found

Twenty trials (1,470 patients) found a bigger steroid dose reduction with modified Zhibai Dihuang added to standard care, with better disease-activity scores and complement 3, and no added adverse effects. The 52-person astragalus plus rehmannia trial found steroid dose reduction was not significantly different, but fewer patients needed extra prednisone (24.0% vs 44.44%) and 24-hour urine protein was lower.

Results

Larger steroid reduction in a pooled review; mixed results in one small trial.

Effect sizes as reported

Steroid dose reduction WMD 3.79 (95% CI 2.58 to 5.01).

Why this rating

Authors call it preliminary; Chinese trials; small trial not clearly blinded; no trial of rehmannia alone.

Form and dose studied

Formula (combination product): rehmannia is mixed with other herbs, so any effect cannot be credited to rehmannia alone.

Who was studied

People with systemic lupus erythematosus or lupus nephritis, China.

Limits

Interaction with steroids and immunosuppressants is not tested; these were add-on studies run under doctors.

Why researchers looked

Steroids cause many side effects in lupus, so reviewers looked for steroid-sparing add-ons.

Traditional use

Zhibai Dihuang is a traditional rehmannia-based formula; its traditional indications were not described in the sources we read.

Proposed mechanism Pharmacological theory

Not tested in the human trials.

A proposed mechanism does not show that the effect happens in people.

Do not change steroid doses on your own.

^{3 16}

Bone loss (osteoporosis): Dihuang decoction versus alendronate, small trial; no placebo trial of rehmannia alone

Very low certainty

One 72-person Chinese trial found a rehmannia-based decoction and the bone drug alendronate both improved bone density and bone markers over a year, with no difference between them. A review of 107 trials calls the trials poorly designed. A planned review of Liuwei Dihuang for osteoporosis has only a protocol.

3 studiesFormula (combination product): rehmannia is mixed with other herbs, s…

Studies, doses and limits

What the trials found

Wan 2019: 72 patients took Dihuang Decoction or alendronate for one year; BMD at femoral neck and lumbar spine improved in both groups, and between-group differences were not significant (P=0.294 and 0.478). The 2017 review identified 107 clinical trials in combination with other herbs and says most report high efficacy but are limited by small size, short duration and poor design. The 2019 meta-analysis of Liuwei Dihuang for osteoporosis is a protocol only.

Results

Similar bone density change as alendronate in one small trial; no placebo comparison.

Effect sizes as reported

No effect size versus placebo; between-group P=0.294 femoral neck, 0.478 lumbar spine.

Why this rating

Single small trial with no placebo; the poorly designed trial pool in the review; one Chinese-language report.

Form and dose studied

Formula (combination product): rehmannia is mixed with other herbs, so any effect cannot be credited to rehmannia alone.

Who was studied

Adults with primary osteoporosis, China.

Limits

Abstract describes dosing unclearly; no fracture outcome.

Why researchers looked

Kidney-tonic herbs are widely used for bone loss in China.

Traditional use

In Chinese medicine bones are linked to the kidney, and rehmannia formulas are used for osteoporosis; traditional use only.

Proposed mechanism Animal research

Lab work (cells and animals) suggests catalpol and other compounds affect bone-cell activity; no human mechanism shown.

A proposed mechanism does not show that the effect happens in people.

Bone drugs should not be replaced by an herb without a doctor.

^{29 20 21}

Rheumatoid arthritis: no controlled trial found

Not enough evidence

Rehmannia is traditionally used for arthritis. A clinical monograph lists no study for it. Our PubMed searches did not find a randomized trial or meta-analysis of rehmannia or a rehmannia formula for rheumatoid arthritis.

2 studiesNot applicable

Studies, doses and limits

What the trials found

No randomized human trial was found.

Results

None.

Effect sizes as reported

None.

Why this rating

No human trial found.

Form and dose studied

Not applicable

Who was studied

Not applicable

Limits

Evidence gap.

Why researchers looked

Traditional use and lab work on catalpol and immune cells.

Traditional use

Traditional use for arthritis is mentioned in the clinical monograph, without a cited study.

Proposed mechanism Animal research

Not established in humans.

A proposed mechanism does not show that the effect happens in people.

Not applicable.

^{17 24}

Anemia and "blood nourishing": mostly traditional and animal evidence

Not enough evidence

Rehmannia is traditionally used to 'nourish blood'. One clinical monograph grades adjunct use in aplastic anemia as C (preliminary). A Si Wu Tang trial found no difference in anemia blood markers from placebo. Mouse work suggests prepared root helped blood counts more than raw root.

4 studiesFormula (combination product): rehmannia is mixed with other herbs, s…

Studies, doses and limits

What the trials found

The monograph's evidence for aplastic anemia dates from 1998 to 2006 and is graded C. In the Si Wu Tang trial (post-hoc analysis of 76 young women with dysmenorrhea), anemia-related blood markers did not change differently from placebo. No randomized trial of rehmannia for anemia in people was found.

Results

No clear benefit for anemia markers in the one controlled analysis.

Effect sizes as reported

Hemogram: no difference vs placebo.

Why this rating

Weak or no controlled human data; Si Wu Tang analysis was post hoc and not in anemic patients specifically.

Form and dose studied

Formula (combination product): rehmannia is mixed with other herbs, so any effect cannot be credited to rehmannia alone.

Who was studied

Young women with period pain (Si Wu Tang trial).

Limits

Not an anemia trial.

Why researchers looked

Traditional blood tonic formulas (Siwu, Bazhen) feature rehmannia.

Traditional use

Prepared root (shu di huang) is the blood tonic; raw root (sheng di huang) is used to cool blood.

Proposed mechanism Animal research

In mice with chemotherapy-induced marrow suppression, processed root improved blood counts more than raw root; iridoid glycosides fell and furfural compounds rose on processing.

A proposed mechanism does not show that the effect happens in people.

Do not treat anemia with herbs without testing the cause.

^{24 32 8 17}

Period pain: Siwu-family formulas (combination)

Low certainty

A 2020 review of five trials found a modified Siwu formula (Taohong Siwu Tang) worked better than painkillers in Chinese trials. A pilot placebo trial of plain Si Wu Tang in Taiwan found no significant difference at the end of treatment. Both formulas contain rehmannia with other herbs.

3 studiesFormula (combination product): rehmannia is mixed with other herbs, s…

Studies, doses and limits

What the trials found

Taohong Siwu: five trials (n=486 in the key comparison) with response RR 1.53 against NSAIDs; reviewers call it moderate-quality evidence. Si Wu Tang: a 78-woman placebo-controlled pilot found pain fell with the formula and rose with placebo, but the end-of-treatment difference was not significant; a later cycle was. Blood pressure rose more with the formula in the post-hoc analysis (about 11.4/8.4 vs 6.4/2.9 mm Hg).

Results

Positive pooled result for the modified formula; null for plain Si Wu Tang at end of treatment.

Effect sizes as reported

RR 1.53 (95% CI 1.37 to 1.72) vs NSAIDs for Taohong Siwu.

Why this rating

Taohong Siwu has extra herbs; only five trials; pilot placebo trial was small; blood pressure signal is exploratory.

Form and dose studied

Formula (combination product): rehmannia is mixed with other herbs, so any effect cannot be credited to rehmannia alone.

Who was studied

Young women with primary dysmenorrhea, China and Taiwan.

Limits

Different formulas (Taohong Siwu vs Si Wu Tang); not rehmannia alone.

Why researchers looked

Si Wu Tang is the classic blood-nourishing formula for women's complaints.

Traditional use

Traditional use for menstrual problems.

Proposed mechanism Pharmacological theory

Not established; the Taiwan trial measured blood flow in the uterine artery as an exploratory marker.

A proposed mechanism does not show that the effect happens in people.

Blood pressure rose more with the formula than placebo in one post-hoc analysis; chance cannot be excluded.

^{12 31 32}

Acne: a rehmannia LEAF extract in a tiny trial

Very low certainty

A 22-woman proof-of-concept trial of a branded rehmannia leaf extract found acne scores fell a bit more than with placebo, though placebo also improved. Leaf extract is a different product from the root.

1 studiesBranded leaf extract (not the root), 100 mg/day for 56 days in the tr…

Studies, doses and limits

What the trials found

Twenty-two women aged 18 to 35 took the extract (100 mg/day) or placebo for 56 days. The acne score fell 21.72% with extract versus 14.20% with placebo at day 28; no safety concerns were reported.

Results

Slightly bigger fall than placebo in a tiny trial.

Effect sizes as reported

GAGS fall 21.72% vs 14.20% at day 28.

Why this rating

Tiny trial; placebo group also improved; authors tied to the sponsor; leaf not root.

Form and dose studied

Branded leaf extract (not the root), 100 mg/day for 56 days in the trial.

Who was studied

22 young women with acne, India/China-linked sponsors.

Limits

Very small.

Why researchers looked

A company-linked trial tested a leaf extract.

Traditional use

None for the leaf in traditional medicine in the sources we read.

Proposed mechanism Pharmacological theory

Not described.

A proposed mechanism does not show that the effect happens in people.

No safety concerns reported in 56 days.

²⁷

Connections to the rest of health

How Rehmannia (Di Huang) connects to the rest of our health knowledge graph. Every link says what kind of connection it is. A safety link (for example to the liver) is a warning, not a benefit. A study that merely mentions a topic never creates a benefit link.

Explore every connection: goals, body systems, organs, symptoms, genes

Kind of connection Connected to Search

A. Wellness goals

Connected to	Kind of connection	Evidence status	Context	Studies
Blood Sugar Balance	Demonstrated clinical effect	Low certainty	Diabetic kidney disease: Liuwei Dihuang-type formulas added to standard care (combination): Several reviews pool Chinese trials in which a rehmannia-containing formula was added to standard diabetes and kidney care. They report less urine albumin and better kidney blood tests. The trials are mostly low quality, and the formula holds six or more herbs, so this does not show what rehmannia does by itself. Type 2 diabetes with chronic kidney disease: one multicentre trial of Rehmannia-6-based granules (combination): One well-run trial in Hong Kong gave patients rehmannia-based granules on top of standard care for 48 weeks. Kidney filtering (eGFR) fell more slowly, but urine albumin did not change significantly. The granules were individualised mixtures, so this is again a combination, not rehmannia alone.	^{4 18 19 6 2}
Metabolic Health	Demonstrated clinical effect	Low certainty	Diabetic kidney disease: Liuwei Dihuang-type formulas added to standard care (combination): Several reviews pool Chinese trials in which a rehmannia-containing formula was added to standard diabetes and kidney care. They report less urine albumin and better kidney blood tests. The trials are mostly low quality, and the formula holds six or more herbs, so this does not show what rehmannia does by itself. Type 2 diabetes with chronic kidney disease: one multicentre trial of Rehmannia-6-based granules (combination): One well-run trial in Hong Kong gave patients rehmannia-based granules on top of standard care for 48 weeks. Kidney filtering (eGFR) fell more slowly, but urine albumin did not change significantly. The granules were individualised mixtures, so this is again a combination, not rehmannia alone.	^{4 18 19 6 2}
Blood Sugar Balance	Preliminary mechanism	Very low certainty	Type 2 diabetes: blood sugar with Liuwei Dihuang pills added to medicines (combination): Two meta-analyses of Chinese trials say adding Liuwei Dihuang pills to diabetes medicines improved fasting and after-meal glucose. They disagree on HbA1c (the three-month average). Study quality was low and rehmannia was never tested alone. Diabetic nerve damage (neuropathy): no human trial found: Reviews mention that rehmannia-based formulas may help diabetic neuropathy, based on small studies and lab work. We did not find a randomized trial of rehmannia, or of a rehmannia formula, for diabetic peripheral neuropathy.	^{23 18 22 14 1 17 13}
Metabolic Health	Preliminary mechanism	Very low certainty	Type 2 diabetes: blood sugar with Liuwei Dihuang pills added to medicines (combination): Two meta-analyses of Chinese trials say adding Liuwei Dihuang pills to diabetes medicines improved fasting and after-meal glucose. They disagree on HbA1c (the three-month average). Study quality was low and rehmannia was never tested alone.	^{23 18 22 14}
Blood Sugar Balance	Potential benefit	Very low certainty	Diabetic eye disease (proliferative retinopathy): herbal combinations that often include rehmannia: A 2023 meta-analysis of 18 trials found better outcomes when herbal combinations were added to eye treatment. Rehmannia was one of the four most-used herbs among 69 herbs. Nothing here isolates rehmannia.	¹⁰
Memory Support	Potential benefit	Very low certainty	Memory and thinking problems: Liuwei Dihuang added to usual care (combination): A 2026 meta-analysis of 12 trials (1,137 people) found higher memory-test scores when Liuwei Dihuang was added to usual care. The authors warn that the trials were weak and varied.	¹¹
Brain Health	Potential benefit	Very low certainty	Memory and thinking problems: Liuwei Dihuang added to usual care (combination): A 2026 meta-analysis of 12 trials (1,137 people) found higher memory-test scores when Liuwei Dihuang was added to usual care. The authors warn that the trials were weak and varied.	¹¹
Inflammation Balance	Preliminary mechanism	Not enough evidence	Rehmannia root on its own: what human evidence exists: Almost no controlled human trial tests plain rehmannia root. A review of 30 Korean papers says the root is effective for inflammatory and metabolic diseases, but its conclusion is stronger than its data. Animal and lab work on the root is plentiful; human proof is not.	^{14 17 13}
Menopause Support	Potential benefit	Very low certainty	Menopause-like symptoms after breast cancer treatment (formulas led by rehmannia): A 2025 meta-analysis of 17 Chinese trials found lower symptom scores with rehmannia-led herbal formulas than with Western medicine. The trials had flaws and varied a lot. The formulas contained other herbs.	¹⁵
Womens Wellness	Potential benefit	Very low certainty	Menopause-like symptoms after breast cancer treatment (formulas led by rehmannia): A 2025 meta-analysis of 17 Chinese trials found lower symptom scores with rehmannia-led herbal formulas than with Western medicine. The trials had flaws and varied a lot. The formulas contained other herbs. Period pain: Siwu-family formulas (combination): A 2020 review of five trials found a modified Siwu formula (Taohong Siwu Tang) worked better than painkillers in Chinese trials. A pilot placebo trial of plain Si Wu Tang in Taiwan found no significant difference at the end of treatment. Both formulas contain rehmannia with other herbs.	^{15 12 31 32}
Immune Support	Demonstrated clinical effect	Low certainty	Lupus: Zhibai Dihuang pill and astragalus-rehmannia pair added to steroids (combination): A 2020 review of 20 trials found people with lupus needed a larger reduction in steroid dose when a rehmannia-based formula (Zhibai Dihuang) was added. A small 2014 trial of an astragalus plus rehmannia pair in lupus kidney disease had mixed results. Both are combinations and the evidence is preliminary.	^{3 16}
Inflammation Balance	Demonstrated clinical effect	Low certainty	Lupus: Zhibai Dihuang pill and astragalus-rehmannia pair added to steroids (combination): A 2020 review of 20 trials found people with lupus needed a larger reduction in steroid dose when a rehmannia-based formula (Zhibai Dihuang) was added. A small 2014 trial of an astragalus plus rehmannia pair in lupus kidney disease had mixed results. Both are combinations and the evidence is preliminary.	^{3 16}
Healthy Aging	Preliminary mechanism	Very low certainty	Bone loss (osteoporosis): Dihuang decoction versus alendronate, small trial; no placebo trial of rehmannia alone: One 72-person Chinese trial found a rehmannia-based decoction and the bone drug alendronate both improved bone density and bone markers over a year, with no difference between them. A review of 107 trials calls the trials poorly designed. A planned review of Liuwei Dihuang for osteoporosis has only a protocol.	^{29 20 21}
Joint Support	Preliminary mechanism	Very low certainty	Bone loss (osteoporosis): Dihuang decoction versus alendronate, small trial; no placebo trial of rehmannia alone: One 72-person Chinese trial found a rehmannia-based decoction and the bone drug alendronate both improved bone density and bone markers over a year, with no difference between them. A review of 107 trials calls the trials poorly designed. A planned review of Liuwei Dihuang for osteoporosis has only a protocol.	^{29 20 21}
Joint Support	Traditional use	Not enough evidence	Rheumatoid arthritis: no controlled trial found: Rehmannia is traditionally used for arthritis. A clinical monograph lists no study for it. Our PubMed searches did not find a randomized trial or meta-analysis of rehmannia or a rehmannia formula for rheumatoid arthritis.	^{17 24}
Inflammation Balance	Traditional use	Not enough evidence	Rheumatoid arthritis: no controlled trial found: Rehmannia is traditionally used for arthritis. A clinical monograph lists no study for it. Our PubMed searches did not find a randomized trial or meta-analysis of rehmannia or a rehmannia formula for rheumatoid arthritis.	^{17 24}
Energy Boost	Traditional use	Not enough evidence	Anemia and "blood nourishing": mostly traditional and animal evidence: Rehmannia is traditionally used to 'nourish blood'. One clinical monograph grades adjunct use in aplastic anemia as C (preliminary). A Si Wu Tang trial found no difference in anemia blood markers from placebo. Mouse work suggests prepared root helped blood counts more than raw root.	^{24 32 8 17}
Reduce Fatigue	Traditional use	Not enough evidence	Anemia and "blood nourishing": mostly traditional and animal evidence: Rehmannia is traditionally used to 'nourish blood'. One clinical monograph grades adjunct use in aplastic anemia as C (preliminary). A Si Wu Tang trial found no difference in anemia blood markers from placebo. Mouse work suggests prepared root helped blood counts more than raw root.	^{24 32 8 17}
Healthy Skin	Potential benefit	Very low certainty	Acne: a rehmannia LEAF extract in a tiny trial: A 22-woman proof-of-concept trial of a branded rehmannia leaf extract found acne scores fell a bit more than with placebo, though placebo also improved. Leaf extract is a different product from the root.	²⁷

B. Body systems

Connected to	Kind of connection	Evidence status	Context	Studies
Urinary system	Drug or supplement interaction	Not enough evidence	Used in kidney trials; catalpol is cleared by the kidneys in rats. Check with a kidney doctor. Preparation or compound: Formulas	^{7 2}
Digestive system	Adverse effect or risk	Not enough evidence	Diarrhea and bloating listed on reference pages. Preparation or compound: Rehmannia root	²⁶
Urinary System	Biological association	Low certainty	Studied for: Diabetic kidney disease: Liuwei Dihuang-type formulas added to standard care (combination) Studied for: Type 2 diabetes with chronic kidney disease: one multicentre trial of Rehmannia-6-based granules (combination)	^{4 18 19 6 2 3 16}
Endocrine System	Biological association	Low certainty	Studied for: Diabetic kidney disease: Liuwei Dihuang-type formulas added to standard care (combination) Studied for: Type 2 diabetes: blood sugar with Liuwei Dihuang pills added to medicines (combination)	^{4 18 19 6 23 22 14 10 1 17 13}
Nervous System	Biological association	Not enough evidence	Studied for: Diabetic nerve damage (neuropathy): no human trial found Studied for: Memory and thinking problems: Liuwei Dihuang added to usual care (combination)	^{22 1 11}
Reproductive System	Biological association	Very low certainty	Studied for: Menopause-like symptoms after breast cancer treatment (formulas led by rehmannia) Studied for: Period pain: Siwu-family formulas (combination)	^{15 12 31 32}
Immune System	Biological association	Very low certainty	Studied for: Menopause-like symptoms after breast cancer treatment (formulas led by rehmannia) Studied for: Lupus: Zhibai Dihuang pill and astragalus-rehmannia pair added to steroids (combination)	^{15 3 16 17 24 32 8}
Musculoskeletal System	Biological association	Very low certainty	Studied for: Bone loss (osteoporosis): Dihuang decoction versus alendronate, small trial; no placebo trial of rehmannia alone Studied for: Rheumatoid arthritis: no controlled trial found	^{29 20 21 17 24}
Integumentary System	Biological association	Very low certainty	Studied for: Acne: a rehmannia LEAF extract in a tiny trial	²⁷

D. Symptoms

Connected to	Kind of connection	Evidence status	Context	Studies
Diabetic kidney disease	Potential benefit	Low certainty	Add-on formulas lowered urine albumin in low-quality trials; rehmannia alone not tested. Preparation or compound: Liuwei Dihuang formula	^{4 2}
Lupus steroid dose	Potential benefit	Low certainty	Preliminary evidence for Zhibai Dihuang as an add-on. Preparation or compound: Zhibai Dihuang formula	³
Digestive upset	Adverse effect or risk	Not enough evidence	Diarrhea and bloating listed on reference pages. Preparation or compound: Rehmannia root	²⁶

I. Biomarkers

Connected to	Kind of connection	Evidence status	Context	Studies
Blood glucose	Drug or supplement interaction	Not enough evidence	Added blood-sugar lowering with diabetes drugs is possible. Preparation or compound: Liuwei Dihuang formula	^{23 18}
Kidney filtering rate (eGFR)	Biological association	Low certainty	Measured in trials: mixed. A lab change is not the same as a health benefit.	²
Urine albumin (UAER / UACR)	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{4 2 18 6}
Serum creatinine and urea nitrogen	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{4 18}
Fasting and after-meal blood glucose	Biological association	Very low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{23 18}
HbA1c (three-month blood sugar average)	Biological association	Very low certainty	Measured in trials: mixed. A lab change is not the same as a health benefit.	^{23 18}
T-cell balance (CD4, CD8, CD4/CD8 ratio)	Biological association	Very low certainty	Measured in trials: mixed. A lab change is not the same as a health benefit.	¹⁵
Bone mineral density and bone turnover (beta-CTX, SOST)	Biological association	Very low certainty	Measured in trials: no-change. A lab change is not the same as a health benefit.	²⁹
Anemia-related blood markers	Biological association	Low certainty	Measured in trials: no-change. A lab change is not the same as a health benefit.	³²

K. Biological pathways

Connected to	Kind of connection	Evidence status	Context	Studies
AMPK/PI3K-Akt and NF-kB signalling	Preliminary mechanism	Animal	Reported for catalpol in animal diabetes models; no human data.	¹
Osteoclast and osteoblast balance	Preliminary mechanism	Animal	Reported in bone models; no human data.	²⁰

L. Active compounds

Connected to	Kind of connection	Evidence status	Context	Studies
Catalpol	Biological association	Animal	The most studied single compound ("drug-like research"): animal models report lower blood sugar, anti-inflammatory and nerve-protective effects; a version was developed as a stroke drug candidate (rat PK paper). No human trial found. Preparation or compound: Root (more in raw than in processed root per mouse-study chemistry: iridoid glycosides decrease with processing)	^{1 7 33 8}
Aucubin	Biological association	Animal	Listed among iridoid glycosides in the 2023 review; no human data. Preparation or compound: Root	¹³
Ajugol	Biological association	Animal	Supposed active component with catalpol and acteoside for bone effects (2017 review); no human data. Preparation or compound: Root	²⁰
Acteoside (verbascoside)	Biological association	Animal	Supposed active component (2017 review); no human data. Preparation or compound: Root	^{20 13}
Rehmannioside D	Biological association	Animal	Named in the 2022 review as a component needing further study; no human data. Preparation or compound: Root, especially prepared root	¹⁷
Polysaccharides and furfural derivatives	Biological association	In vitro	Iridoid glycosides decreased and furfural derivatives increased after nine cycles of rice-wine processing in one analysis. Preparation or compound: Root; furfural compounds increase on processing	^{8 13}

Each connection is stored with the ingredient, the connected record, the kind of connection, the evidence status, the supporting studies, the preparation or compound involved, and a review date (last reviewed October 25, 2026).

Evidence at a glance: what changed in 8 lab markers

Tap a number to show only those markers. Counts are markers, not people.

Metabolic11 Organ function111 Other111

The evidence

The research centre for Rehmannia (Di Huang). Every record here was checked against PubMed or the publisher's page; we never list a study we have not verified.

Evidence by outcome

Diabetic kidney disease: Liuwei Dihuang-type formulas added to standard care (combination) 4 studies Low certainty Type 2 diabetes with chronic kidney disease: one multicentre trial of Rehmannia-6-based granules (combination) 1 studies · 148 people in trials Low certainty Type 2 diabetes: blood sugar with Liuwei Dihuang pills added to medicines (combination) 4 studies Very low certainty Diabetic eye disease (proliferative retinopathy): herbal combinations that often include rehmannia 1 studies Very low certainty Diabetic nerve damage (neuropathy): no human trial found 2 studies Not enough evidence Memory and thinking problems: Liuwei Dihuang added to usual care (combination) 1 studies Very low certainty Rehmannia root on its own: what human evidence exists 3 studies Not enough evidence Menopause-like symptoms after breast cancer treatment (formulas led by rehmannia) 1 studies Very low certainty Lupus: Zhibai Dihuang pill and astragalus-rehmannia pair added to steroids (combination) 2 studies · 52 people in trials Low certainty Bone loss (osteoporosis): Dihuang decoction versus alendronate, small trial; no placebo trial of rehmannia alone 3 studies · 72 people in trials Very low certainty Rheumatoid arthritis: no controlled trial found 2 studies Not enough evidence Anemia and "blood nourishing": mostly traditional and animal evidence 4 studies · 76 people in trials Not enough evidence Period pain: Siwu-family formulas (combination) 3 studies · 154 people in trials Low certainty Acne: a rehmannia LEAF extract in a tiny trial 1 studies · 22 people in trials Very low certainty

Bars show how many studies we found for each outcome, not how well it works. People are added up across trials only (reviews are not added, to avoid double counting).

How we rate evidence

High certainty

Several well-run trials or reviews agree; further research is unlikely to change the picture much.

Moderate certainty

Good trials point the same way, but some doubt remains.

Low certainty

Small, short or inconsistent trials. The finding could change with better research.

Very low certainty

Very little or very weak human data. Treat as a possibility only.

Mixed findings

Trials or reviews disagree with each other.

Not enough evidence

Not enough human research to say either way.

Evidence against

Good research found no benefit, or found harm.

We take the reviewers' own risk-of-bias and GRADE statements where they exist, and otherwise judge from study size, design, consistency, directness and whether a product matches what is sold. Many publications do not make evidence high. Method note: We searched PubMed, read abstracts, checked GBIF, NCBI Taxonomy and PubChem, and read the Restorative Medicine monograph, an RxList page and Hobbs database. We could not find EMA/HMPC, NCCIH, LiverTox, LactMed or WHO entries; these are marked not found, not confirmed absent. A Royal College of Physicians garden snippet could not be read and is unverified. Certainty ratings are the compiler's own reading. No study is cited that we could not verify.

Study library: every study we checked 33

Design Research type Plant part Year from Search

Study	Design	People	Product, dose, length	Result
Bai 2019 Catalpol in Diabetes and its Complications: A Review of Pharmacology, Pharmacokinetics, and Safety. Molecules · PMID 31514313 · DOI	Narrative review animal	Review of more than 100 publications on catalpol	Catalpol (purified iridoid glycoside) isolated compound not stated in abstract not stated in abstract	Catalpol lowered blood sugar in animal models at 2.5 to 200 mg/kg in rats and 10 to 200 mg/kg in mice. It can cross the blood-brain barrier and is described as well tolerated. No clinical trial is described in the abstract. Animal data only Methods, limits and funding Outcomes: Pharmacology, pharmacokinetics, safety Limitations: Animal and cell data; authors call for clinical trials. Catalpol is only one compound of the root. Read: abstract
Chan 2023 Add-on Rehmannia-6-Based Chinese Medicine in Type 2 Diabetes and CKD: A Multicenter Randomized Controlled Trial. Clin J Am Soc Nephrol · PMID 37307005 · DOI	Controlled trial	148 Adults with type 2 diabetes, eGFR 30-90, severely raised urine albumin, Hong Kong	Rehmannia-6-based Chinese medicine granules (a protocol of individualised multi-herb formulas) root (as part of formulas) not stated in abstract 48 weeks · vs Standard care alone	eGFR fell by 2.0 per year with add-on Chinese medicine and 4.7 with standard care alone. UACR change did not differ significantly. 2.7 ml/min per 1.73 m2 per year less eGFR decline (P=0.04); UACR difference not significant (P=0.28) (eGFR difference 0.1 to 5.3; UACR ratio 0.89 (0.72 to 1.10)) Methods, limits and funding Outcomes: Slope of eGFR and urine albumin-to-creatinine ratio (UACR) over 48 weeks Limitations: Open to bias in participants and doctors (only assessors were blinded); no placebo; individualised multi-herb formulas, so rehmannia alone is not tested; 8 of 148 primary outcome measures missing. Funding and conflicts: Some authors report industry funding or consultancy for diabetes and kidney drug companies; the Chinese medicine arm itself was university-run (details not in abstract). Registration: NCT02488252 Read: abstract
Dai 2020 Modified Zhibai Dihuang pill, a traditional Chinese medicine formula, on steroid withdrawal in systemic lupus erythematosus: A systematic review and meta-analysis. J Integr Med · PMID 32907784 · DOI	Meta-analysis	1470 People with systemic lupus erythematosus; 20 trials	Modified Zhibai Dihuang pill (rehmannia-containing formula) with standard care root as part of a formula not stated in abstract not stated in abstract · vs Standard care containing steroids	Larger steroid dose reduction with the formula; disease activity measures also favoured it; no added adverse effects reported. Steroid dose reduction WMD 3.79 (2.58 to 5.01) Methods, limits and funding Outcomes: Steroid dose reduction, SLEDAI disease activity, complement 3 Limitations: Authors call the evidence preliminary; trials were mostly Chinese and the abstract gives no bias rating. Read: abstract
Du 2026 Impact of liuwei dihuang pills (decoction) on early diabetic nephropathy: a systematic review and meta-analysis. Front Med (Lausanne) · PMID 42051693 · DOI	Meta-analysis	1007 Adults with early diabetic nephropathy; 11 randomized trials, mostly Chinese	Liuwei Dihuang pills or decoction (six-herb formula) added to conventional treatment root (prepared) as part of a six-herb formula not stated in abstract not stated in abstract · vs Conventional treatment alone	Lower UAER, creatinine and urea nitrogen with the formula added. Adverse events reported in only 6 of 11 trials: 12/287 vs 12/277. UAER mean difference -37.30; creatinine -5.96; urea nitrogen -0.91; adverse events OR 0.99 (UAER -47.51 to -27.09; creatinine -9.27 to -2.65; adverse events 0.43 to 2.30) Methods, limits and funding Outcomes: Urinary albumin excretion rate (UAER), creatinine, urea nitrogen, adverse events Limitations: Authors rate overall quality low: no allocation concealment or blinding, large variation (I2 93% for UAER), incomplete safety reporting. Funding and conflicts: None declared Registration: PROSPERO CRD420261280431 Read: abstract
GBIF Secretariat 2026 GBIF backbone: Rehmannia glutinosa (Gaertn.) Libosch. ex Fisch. & C.A.Mey. (usageKey 7516558) GBIF API · Source	Database	Plant taxonomy record	Rehmannia (Rehmannia glutinosa root) root n/a n/a	Accepted name Rehmannia glutinosa (Gaertn.) Libosch. ex Fisch. & C.A.Mey., family Rehmanniaceae, order Lamiales. "Rehmannia glutinosa (Gaertn.) DC." and "(Gaertn.) Steud." are listed as synonyms. Match was exact, confidence 99. Not a trial Methods, limits and funding Outcomes: Safety, regulatory and clinical-use information Limitations: Database record, queried 2026-10-25. Read: full-text
Gao 2018 A Meta-Analysis of the Clinical Efficacy of TCM Decoctions Made from Formulas in the Liuwei Dihuang Wan Categorized Formulas in Treating Diabetic Nephropathy Proteinuria. Evid Based Complement Alternat Med · PMID 30356440 · DOI	Meta-analysis	Patients with diabetic nephropathy proteinuria; 14 studies	Decoctions of Liuwei Dihuang-family formulas root as part of formulas not stated in abstract not stated in abstract	Better overall efficacy and lower urine protein than comparators; no serious adverse reactions reported. Overall efficacy OR 2.87; 24-h urinary protein MD 0.12; microalbumin SMD 0.87 (OR 1.98 to 4.15) Methods, limits and funding Outcomes: Overall efficacy, 24-hour urine protein, urine microalbumin excretion Limitations: Abstract does not give a bias rating or total patient number. Formulas varied. Read: abstract
Ge 2023 Pharmacokinetics, Mass Balance, Tissue Distribution, and Metabolism of [(3)H]Catalpol in Rats: the Main Bioactive Component of Rehmannia glutinosa for the Treatment of Ischemic Stroke. Curr Drug Metab · PMID 37409552 · DOI	Animal pharmacokinetic study animal	Rats	Single oral dose of radiolabelled catalpol (30 mg/kg) isolated compound not stated in abstract not stated in abstract	Rapidly absorbed (median Tmax 0.75 h, plasma half-life of radioactivity about 1.52 h). About 94.8% of the radioactivity was recovered over 168 h: 57.5% in urine and 37.3% in faeces. Parent catalpol was the main substance in plasma and urine; gut bacteria appear to make the metabolites. Rat data Methods, limits and funding Outcomes: Absorption, distribution, metabolism, excretion Limitations: Rat study; a catalpol drug developer is named as the sponsor of the compound; no human data. Funding and conflicts: Catalpol was developed by Suzhou Youseen (named in abstract). Read: abstract
Gong 2019 Comparisons of antithrombosis, hematopoietic effects and chemical profiles of dried and rice wine-processed Rehmanniae Radix extracts. J Ethnopharmacol · PMID 30359761 · DOI	Animal study animal	Mice (blood-clot and bone-marrow suppression models)	Aqueous extract of dried (raw) root versus rice-wine-processed root (nine cycles) root, raw vs processed not stated in abstract not stated in abstract	Raw root extract reduced clotting in mice more than processed root; neither changed prothrombin time or APTT; processed root improved blood counts more. Iridoid glycosides fell and furfural compounds rose with processing. Mouse data Methods, limits and funding Outcomes: Tail clot size, blood flow, clotting times, blood counts, bone marrow cells Limitations: Mouse study only; does not show the same in people. Read: abstract
Hobbs n.d. Rehmannia, herbal therapeutics database (Christopher Hobbs) christopherhobbs.com · Source	Herbal database	Practitioner herbal database	Rehmannia (Rehmannia glutinosa root) root n/a n/a	Says rehmannia is generally considered safe when used appropriately; side effects may include stomach upset or dizziness; avoid in severe diarrhea or spleen deficiency (a traditional concept), weak digestion or poor appetite; says it may interact with immunosuppressants, diuretics and corticosteroids; pregnancy and breastfeeding: insufficient evidence. Not a trial Methods, limits and funding Outcomes: Safety, regulatory and clinical-use information Limitations: Secondary database; no mechanism or study is given for the interaction statement. Read: full-text
Huai 2023 Systematic evaluation of combined herbal adjuvant therapy for proliferative diabetic retinopathy. Front Endocrinol (Lausanne) · PMID 37274344 · DOI	Meta-analysis	1392 People with proliferative diabetic retinopathy; 18 trials	Combined Chinese herbal adjuvant therapy (69 herbs across trials; rehmannia among the four most used) mixed not stated in abstract not stated in abstract	Better effective rate and vision, and lower fasting glucose, than control. Authors note few trials and the need to study safety. Effective rate OR 2.99; visual acuity MD 0.10 (OR 2.18 to 4.10) Methods, limits and funding Outcomes: Clinical effective rate, vision, new vessel regression, vitreous haemorrhage absorption, glucose Limitations: Many different herbs; not a rehmannia product; high variation for some outcomes (I2 up to 95.6%). Funding and conflicts: None declared Read: abstract
Hwang 2026 Effectiveness and Safety of Liuwei Dihuang as an Adjunctive Therapy for Cognitive Impairment: A Systematic Review, Meta-Analysis, and Network Pharmacology Analysis. Pharmaceuticals (Basel) · PMID 42198453 · DOI	Meta-analysis	1137 People with cognitive disorders (dementia and related); 12 randomized trials	Liuwei Dihuang added to conventional therapy root as part of a six-herb formula not stated in abstract not stated in abstract · vs Conventional therapy alone	Higher MMSE scores with the formula added; fewer adverse events reported in the formula group, with limited reporting. The network pharmacology part is computer prediction only. MMSE MD 2.34 (0.88 to 3.79) Methods, limits and funding Outcomes: Mini-Mental State Examination (MMSE), daily living, quality of life, adverse events Limitations: Authors: unclear randomization and blinding, large variation; overall risk of bias "some concerns". Funding and conflicts: None declared Read: abstract
Ji 2020 Herbal medicine (Taohong Siwu Tang) for the treatment of primary dysmenorrhea: A systematic review and meta-analysis. Explore (NY) · PMID 32723605 · DOI	Meta-analysis	486 People with primary dysmenorrhea; 5 trials	Taohong Siwu Tang (modified Siwu decoction; Siwu is a rehmannia-containing four-herb formula, with added herbs) root as part of a formula not stated in abstract not stated in abstract · vs NSAIDs / oral contraceptives	Better response than NSAIDs (n=486); one trial found lower recurrence than NSAIDs; plus oral contraceptives did better than contraceptives alone (n=60). RR 1.53 vs NSAIDs (1.37 to 1.72) Methods, limits and funding Outcomes: Treatment response, recurrence Limitations: Only 5 trials; the formula has added herbs (peach kernel and safflower per its name); reviewers wrote "moderate quality evidence". Funding and conflicts: None declared Read: abstract
Jia 2023 Progress of research into the pharmacological effect and clinical application of the traditional Chinese medicine Rehmanniae Radix. Biomed Pharmacother · PMID 37907043 · DOI	Narrative review	Review of pharmacology and clinical use of Rehmanniae Radix	Rehmanniae Radix and formulas (Liuwei, Siwu) root not stated in abstract not stated in abstract	Lists iridoid glycosides (catalpol), phenylpropanoid glycosides and polysaccharides as active parts; discusses limits of current research. Not a trial Methods, limits and funding Outcomes: Chemical constituents, pharmacology, clinical application Limitations: Narrative review. Read: abstract
Kim 2017 Rehmanniae Radix, an Effective Treatment for Patients with Various Inflammatory and Metabolic Diseases: Results from a Review of Korean Publications. J Pharmacopuncture · PMID 30087783 · DOI	Narrative review	30 Korean-language publications on Rehmanniae Radix	Rehmanniae Radix (mixed forms) root not stated in abstract not stated in abstract	The authors conclude the root is effective for inflammatory and metabolic diseases; this is a review of 30 mostly small Korean publications and its conclusion is stronger than its data. Not a trial Methods, limits and funding Outcomes: Antioxidant effects, blood glucose, autonomic nervous system, human body effects Limitations: Small, uneven literature; strong conclusion not supported by controlled trial data in the abstract. Funding and conflicts: None declared Read: abstract
Kong 2025 Rehmannia glutinosa for perimenopausal syndrome in patients with breast cancer: A systematic review and meta-analysis. Saudi Med J · PMID 40628433 · DOI	Meta-analysis	1139 Breast cancer patients with perimenopausal syndrome; 17 trials	Chinese herbal medicine with Rehmannia glutinosa as the main (monarch) herb, plus other herbs root as part of formulas not stated in abstract not stated in abstract · vs Western medicine	Lower symptom score and better CD4/CD8 profile than Western medicine; quality-of-life (FACT-B) and hormone levels did not differ; no severe adverse reactions. Kupperman index MD -12.79 (p<0.01) Methods, limits and funding Outcomes: Kupperman index (menopause symptom score), performance status, T-cell percentages, hormones, adverse events Limitations: Authors: methodological flaws and high variation. The comparator was Western medicine, not placebo. Mixed formulas. Read: abstract
Li 2014 [Treating lupus nephritis by a drug pair of radix astragali and rehmanniae radix combined with glucocorticoid: a preliminary clinical study]. Zhongguo Zhong Xi Yi Jie He Za Zhi · PMID 25223180	Controlled trial	52 People with lupus nephritis, China	Astragalus root plus Rehmannia root pair added to glucocorticoids and standard drugs root not stated in abstract 6 months · vs Western medicine (glucocorticoid and cyclophosphamide)	Steroid dose reduction did not differ significantly; fewer patients needed added prednisone; 24-hour urine protein was lower; some steroid-related effects were less common. Added prednisone needed in 24.0% vs 44.44% (P<0.05) Methods, limits and funding Outcomes: Steroid withdrawal/reduction, SLEDAI, urine protein, adverse reactions Limitations: Small; not blinded as far as the abstract says; a two-herb pair, so rehmannia alone is not tested. Read: abstract
Li 2022 A systematic review on botany, processing, application, phytochemistry and pharmacological action of Radix Rehmnniae. J Ethnopharmacol · PMID 34767834 · DOI	Systematic review	Literature review of botany, processing, uses, chemistry and lab effects of Radix Rehmanniae	Dried (raw) root and processed root (RRP) root not stated in abstract not stated in abstract	Over 100 compounds identified. Raw and processed root differ in property, chemistry and effects. The authors say the reasons for these differences still need testing and that catalpol does not represent the whole root. Not a trial Methods, limits and funding Outcomes: Chemistry, traditional use, processing, lab pharmacology Limitations: Mostly lab and traditional use; the review itself says standardising processing is needed. Read: abstract
Lin 2016 Liuwei Dihuang Pills Enhance the Effect of Western Medicine in Treating Diabetic Nephropathy: A Meta-Analysis of Randomized Controlled Trials. Evid Based Complement Alternat Med · PMID 26997962 · DOI	Meta-analysis	1275 Patients with diabetic nephropathy; 18 trials	Liuwei Dihuang pills added to Western medicine root (prepared) as part of a six-herb formula not stated in abstract not stated in abstract · vs Western medicine alone	Added pills lowered fasting and after-meal glucose and several kidney measures; HbA1c change was not significant (P=0.43). Fasting glucose MD -0.36; after-meal glucose MD -1.10; HbA1c MD -0.14 (not significant); UAER MD -26.18 (Fasting glucose -0.46 to -0.25; HbA1c -0.49 to 0.21) Methods, limits and funding Outcomes: Blood glucose, kidney function, adverse events Limitations: Authors: methodological quality of trials generally low and evidence remains weak. Read: abstract
Lin 2023 Efficacy of "Dihuang pill prescriptions" combined with conventional treatment for diabetic kidney disease: A network meta-analysis and systematic review. Medicine (Baltimore) · PMID 37773831 · DOI	Meta-analysis	3562 Patients with diabetic kidney disease; 41 randomized trials, four Dihuang-pill formulas	Four formula families (Liuwei, Zhibai, Jingui Shenqi, Jisheng Shenqi Dihuang) added to conventional treatment root as part of formulas not stated in abstract not stated in abstract	All four formula families ranked better than conventional treatment alone on several measures. Zhibai Dihuang and Liuwei Dihuang ranked top for lowering UAER. Ranked by SUCRA; no single effect size in the abstract Methods, limits and funding Outcomes: 24-hour urine protein, UAER, creatinine, fasting glucose, effective rate Limitations: Network ranking from small Chinese trials; abstract gives no bias rating; formulas differ by added herbs. Funding and conflicts: None declared Read: abstract
Liu 2017 Rehmanniae Radix in osteoporosis: A review of traditional Chinese medicinal uses, phytochemistry, pharmacokinetics and pharmacology. J Ethnopharmacol · PMID 28111216 · DOI	Narrative review	Review of about 330 papers on Rehmanniae Radix in osteoporosis	Rehmanniae Radix alone and in combination root not stated in abstract not stated in abstract	Identifies 107 clinical trials using the root in combination with other herbs for osteoporosis; the authors say most report high efficacy and no obvious adverse effects but are limited by small size, short treatment, poor design and unclear herbs. Not a pooled analysis Methods, limits and funding Outcomes: Clinical trials, pharmacokinetics, bone cell studies Limitations: Authors state the clinical trials are poorly designed and unstandardised. Read: abstract
Liu 2019 Liuwei Dihuang Decoction for primary osteoporosis: A protocol for a systematic review and meta-analysis. Medicine (Baltimore) · PMID 31008975 · DOI	Protocol	Planned review of Liuwei Dihuang Decoction for primary osteoporosis	Liuwei Dihuang Decoction root as part of a formula not stated in abstract not stated in abstract	This is a protocol only. It has no results. No results Methods, limits and funding Outcomes: Planned: fracture incidence Limitations: Protocol; results not found in our search. Registration: PROSPERO CRD 4201926066 (as printed in the abstract) Read: abstract
Poon 2011 Review of the effects of the traditional Chinese medicine Rehmannia Six Formula on diabetes mellitus and its complications. J Diabetes · PMID 21631896 · DOI	Narrative review	Literature review 2000-2009 on Rehmannia Six Formula (Liuwei Dihuang) in diabetes	Rehmannia Six Formula (Liu Wei Di Huang Wan) root as part of a six-herb formula not stated in abstract not stated in abstract	The authors say the formula appears to help blood glucose, neuropathy and nephropathy but there are few studies of the formula as a whole; clinical studies are warranted. Not a trial Methods, limits and funding Outcomes: Blood glucose, neuropathy, nephropathy, inflammation and antioxidant effects Limitations: Narrative review; not systematic in its reporting; many studies are on single compounds. Read: abstract
Pu 2013 Liuwei dihuang pills enhance the effect of Western medicine in treating type 2 diabetes: A meta-analysis of randomized controlled trials. Chin J Integr Med · PMID 24092243 · DOI	Meta-analysis	1609 Adults with type 2 diabetes; 18 studies	Liuwei Dihuang pills added to Western diabetes drugs root (prepared) as part of a six-herb formula not stated in abstract not stated in abstract · vs Western drugs alone	Add-on pills improved glucose measures and response rates. Authors: study methodological quality was less adequate than expected. Fasting glucose MD 0.54 mmol/L, 2-hour glucose MD 1.05, HbA1c MD 0.23 (differences as reported, in favour of the pills); response OR 3.41 (Fasting glucose 0.15 to 0.93; HbA1c 0.02 to 0.45) Methods, limits and funding Outcomes: Fasting glucose, 2-hour glucose, HbA1c, response rates Limitations: Low study quality; the abstract does not say how the direction of mean differences was defined; formula, not rehmannia alone. Read: abstract
Restorative Medicine n.d. Rehmannia monograph (Restorative Medicine library) restorativemedicine.org · Source	Clinical monograph	Clinical monograph for practitioners	Rehmannia (Rehmannia glutinosa root) root n/a n/a	Grades both listed evidence-based uses C (aplastic anemia as an adjunct, and Sheehan syndrome); cites studies dated 1998 to 2006. Lists the root in the Pharmacopoeia of the PRC; not on the UK General Sale List; no German Commission E monograph; no FDA GRAS status; sold in the US as a dietary supplement. States no proven safe or effective dose for children. Does not address adverse effects, contraindications, pregnancy or drug interactions. Not a trial Methods, limits and funding Outcomes: Safety, regulatory and clinical-use information Limitations: Secondary clinical monograph; the grading scale is not defined on the page; not a regulator. Read: full-text
Royal College of Physicians n.d. Royal College of Physicians garden database entry for Rehmannia (via search result) garden.rcp.ac.uk · Source	Database snippet	Garden plant database note, seen only as a search-result snippet	Rehmannia (Rehmannia glutinosa root) root n/a n/a	The snippet said the root is contraindicated in chronic liver or gastrointestinal diseases and in diarrhoea, attributed to a WHO-based summary. NOT verified: the page redirected and we could not read it, and no WHO monograph was found. Not a trial Methods, limits and funding Outcomes: Safety, regulatory and clinical-use information Limitations: NOT verified. Search snippet only. Read: summary-only
RxList 2026 Sheng Di Huang (Rehmannia glutinosa) drug-reference page (RxList) rxlist.com · Source	Drug reference page	Consumer drug reference page	Rehmannia (Rehmannia glutinosa root) root n/a n/a	Rated "possibly effective" on in vitro and animal data. Lists diarrhea and abdominal distension as side effects. Lists no known drug interactions but says the list is incomplete. States that no information is available for pregnancy or breastfeeding. Contraindication listed: hypersensitivity. Not a trial Methods, limits and funding Outcomes: Safety, regulatory and clinical-use information Limitations: Consumer reference page; gives no sources for its statements; says it does not list all effects. Read: full-text
Srivastava 2024 Assessment of the Effect of Rehmannia glutinosa Leaf Extract in Maintaining Skin Health: A Proof-of-Concept, Double-Blind, Randomized, Placebo-Controlled Clinical Trial. Clin Cosmet Investig Dermatol · PMID 38651075 · DOI	Controlled trial	22 Women aged 18-35 with moderate to severe acne, India	Rehmannia glutinosa leaf extract (a branded extract), not the root leaf 100 mg/day 56 days · vs Placebo	Acne scores fell in both groups, a little more with the extract; no safety concern reported. GAGS reduced 21.72% vs 14.20% at day 28 Methods, limits and funding Outcomes: Global Acne Grading System score and skin measures at day 56 Limitations: Proof-of-concept with 22 women; the placebo group also improved; leaf extract is a different product from the root. Funding and conflicts: Authors are linked to the maker or its partner companies (Vedic Lifesciences, NuLiv). Read: abstract
Teschke 2015 Traditional Chinese Medicine and herbal hepatotoxicity: a tabular compilation of reported cases. Ann Hepatol · PMID 25536637	Systematic review	Worldwide case reports of liver injury from traditional Chinese medicine; 77 publications, 57 herbs and mixtures	Traditional Chinese herbs and mixtures various not stated in abstract not stated in abstract	Causality was established for 28 of 57 herbs or mixtures. The abstract lists them; Di Huang (rehmannia) is not among the names listed in the abstract. Not specific to rehmannia Methods, limits and funding Outcomes: Causality of liver injury by CIOMS scale Limitations: We read only the abstract, not the full tables. Read: abstract
Wan 2019 [Comparison of the clinical effects between Dihuang Decoction and alendronate sodium in the treatment of primary osteoporosis]. Zhongguo Gu Shang · PMID 31277537 · DOI	Controlled trial	72 Adults with primary osteoporosis, China	Dihuang Decoction (Rehmannia decoction), a multi-herb decoction root as part of a decoction not stated in abstract 1 year · vs Alendronate 70 mg weekly	Both groups improved; the two groups did not differ. Between-group BMD P=0.294 (femoral neck) and 0.478 (lumbar spine) Methods, limits and funding Outcomes: Bone mineral density at femoral neck and lumbar spine, beta-CTX, SOST after 1 year Limitations: Small; no placebo; compared with alendronate and not rehmannia alone; the abstract describes dosing unclearly; Chinese-language journal. Read: abstract
Xiao 2025 The coexistence characteristics of microplastics and heavy metals in rhizomes of traditional Chinese medicine in mulch planting area. Environ Geochem Health · PMID 39937393 · DOI	Laboratory study in-vitro	Eight rhizome herbs sampled from a mulch-planting area in China	Powdered rhizome herbs including Rehmannia glutinosa root not stated in abstract not stated in abstract	Microplastics were common (20.83 to 43.65 items/g across the herbs). The estimated daily intake of microplastics and heavy metals was higher for Rehmannia glutinosa and one other herb than for the rest. Contamination found Methods, limits and funding Outcomes: Microplastics and heavy metals Limitations: A single growing area; no retail product test; no exposure numbers for rehmannia in the abstract. Read: abstract
Yeh 2007 A randomised placebo-controlled trial of a traditional Chinese herbal formula in the treatment of primary dysmenorrhoea. PLoS One · PMID 17710126 · DOI	Controlled trial	78 Young women with primary dysmenorrhoea, Taiwan	Four-Agents-Decoction (Si Wu Tang) capsules, 15 per day for five days per cycle root as part of a four-herb formula 15 capsules/day for 5 days per cycle 3-4 treatment cycles · vs Placebo	Pain fell with the formula and rose with placebo, but the end-of-treatment difference was not statistically significant; no difference in adverse symptoms. Not significant at end of treatment Methods, limits and funding Outcomes: Pain intensity on a visual scale Limitations: Pilot trial; a later follow-up cycle was significant, which the authors call unexpected. Registration: ISRCTN23374750 Read: abstract
Yeh 2009 Anemia-related hemogram, uterine artery pulsatility index, and blood pressure for the effects of Four-Agents-Decoction (Si Wu Tang) in the treatment of primary dysmenorrhea. J Altern Complement Med · PMID 19413507 · DOI	Controlled trial	76 Young women with primary dysmenorrhea in Taiwan (post-hoc analysis)	Four-Agents-Decoction (Si Wu Tang) capsules root as part of a four-herb formula not stated in abstract not stated in abstract · vs Placebo	Anemia-related blood markers did not change differently from placebo. Pain, uterine artery index and blood pressure changed more with the formula; the blood pressure rose by 11.4/8.36 mm Hg vs 6.36/2.91 with placebo. Hemogram: no difference vs placebo Methods, limits and funding Outcomes: Anemia blood markers, uterine artery pulsatility index, pain, blood pressure Limitations: Post-hoc analysis of a pilot trial; authors found no strong statistical significance. Read: abstract
Zhao 2009 Decontamination of organochlorine pesticides residue and heavy metal in Rehmannia glutinosa Libosch by SFE. J Chromatogr Sci · PMID 19930806 · DOI	Laboratory study in-vitro	Rehmannia glutinosa root samples	Supercritical CO2 extraction to remove pesticides and metals root not stated in abstract not stated in abstract	A method to remove 12 organochlorine pesticide residues and seven heavy metals from the root with little loss of catalpol. The abstract does not give how much was in the starting samples. Method study Methods, limits and funding Outcomes: 12 organochlorine pesticides and seven heavy metals Limitations: Method paper; shows these contaminants were a concern for the root but gives no market survey. Read: abstract

What we do not know yet

What the evidence supports: add-on formula trials, low or very low certainty.
What is uncertain: whether rehmannia itself, raw or prepared, does anything; no trial of rehmannia alone.
No randomized trial for rheumatoid arthritis or diabetic neuropathy.
No raw versus prepared comparison in people.
No human trial of catalpol.
No human interaction, pregnancy or breastfeeding data.
No retail contamination or adulteration survey.
EMA/HMPC, NCCIH, LiverTox, LactMed and WHO entries not found (not confirmed absent).
Only abstracts were read for most studies. Dosage and product comparison are not covered yet. For amounts, ask a doctor or pharmacist.

How new research is added

New studies are found by a saved PubMed search and placed in a review queue. A person reads each one before it changes any rating or safety wording.

Lab markers

What changed in blood or saliva tests during trials. A changed number is not the same as feeling or being healthier, and we give no "normal ranges".

Metabolic 2

▼

Fasting and after-meal blood glucose

Lowered in trials

Blood sugar measured after fasting or two hours after a meal.

Very low certainty

Results and what it means

Why it was measured

Basic diabetes control measure.

Statistical vs. clinical meaning

Small changes in low-quality add-on trials.

Safety implication

Extra blood-sugar lowering on top of diabetes drugs; discuss with the prescriber.

Study	Result	People	Product
²³	Fasting glucose MD 0.54 mmol/L (0.15 to 0.93); 2-hour glucose 1.05 (0.29 to 1.81), reported in favour of the pills.	1,609 patients, 18 studies	Liuwei Dihuang pills added to Western drugs
¹⁸	Fasting glucose MD -0.36 (-0.46 to -0.25); after-meal glucose -1.10 (-1.35 to -0.85).	1,275 patients, 18 studies	Liuwei Dihuang pills added to Western medicine

^{23 18}

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HbA1c (three-month blood sugar average)

Mixed results in trials

Share of haemoglobin with sugar attached; shows average glucose.

Very low certainty

Results and what it means

Why it was measured

Long-term diabetes control.

Statistical vs. clinical meaning

The two meta-analyses disagree.

Safety implication

None specific.

Study	Result	People	Product
²³	HbA1c MD 0.23 (0.02 to 0.45) in favour of pills.	1,609 patients	Liuwei Dihuang pills added
¹⁸	HbA1c MD -0.14 (-0.49 to 0.21), P=0.43, not significant.	1,275 patients	Liuwei Dihuang pills added

^{23 18}

Organ function 3

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Kidney filtering rate (eGFR)

Mixed results in trials

A blood-test estimate of how well the kidneys filter, in ml/min per 1.73 m2.

Low certainty

Results and what it means

Why it was measured

Tracks kidney function decline over time.

Statistical vs. clinical meaning

A slower decline, not a rise. The confidence interval nearly includes zero; clinical meaning not shown.

Safety implication

People with kidney disease should not add herbs without their kidney doctor.

Study	Result	People	Product
²	Slope fell 2.0 per year with add-on Rehmannia-6-based Chinese medicine vs 4.7 with standard care (difference 2.7, 95% CI 0.1 to 5.3, P=0.04); both groups declined.	148 adults with type 2 diabetes and CKD	Rehmannia-6-based granules (combination) for 48 weeks

▼

Serum creatinine and urea nitrogen

Lowered in trials

Waste products measured in blood; higher levels suggest poorer kidney function.

Low certainty

Results and what it means

Why it was measured

Common kidney function test.

Statistical vs. clinical meaning

Statistical improvement in low-quality trials.

Safety implication

Kidney function should be monitored by a doctor.

Study	Result	People	Product
⁴	Creatinine MD -5.96 (-9.27 to -2.65); urea nitrogen MD -0.91 (-1.46 to -0.36). Units not given in the abstract.	11 trials, 1,007 patients	Liuwei Dihuang added to standard care

^{4 18}

●

Anemia-related blood markers

No clear change in trials

Blood tests used to judge anemia (haemoglobin and related).

Low certainty

Results and what it means

Why it was measured

Check whether a blood-nourishing formula changes anemia status.

Statistical vs. clinical meaning

Not an anemia trial.

Safety implication

None.

Study	Result	People	Product
³²	Anemia-related markers did not change differently from placebo after Si Wu Tang.	76 young women with dysmenorrhea (post-hoc)	Four-Agents-Decoction (combination) vs placebo

³²

Other 3

▼

Urine albumin (UAER / UACR)

Lowered in trials

Protein (albumin) leaking into urine; a marker of kidney damage.

Low certainty

Results and what it means

Why it was measured

Used to monitor diabetic kidney disease.

Statistical vs. clinical meaning

Meta-analysis shows a big drop but very high variation; the single better-designed trial found no significant change.

Safety implication

None specific.

Study	Result	People	Product
⁴	UAER MD -37.30 (95% CI -47.51 to -27.09), I2 93%.	1,007 patients, 11 trials	Liuwei Dihuang added to standard care
²	UACR ratio 0.89 (0.72 to 1.10), not significant.	148 adults	Rehmannia-6-based granules for 48 weeks

^{4 2 18 6}

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T-cell balance (CD4, CD8, CD4/CD8 ratio)

Mixed results in trials

Percentages of two types of white blood cells; the ratio is an immune lab marker.

Very low certainty

Results and what it means

Why it was measured

Used in cancer trials to describe immune status.

Statistical vs. clinical meaning

A lab marker; it does not by itself mean better health.

Safety implication

Immune effects matter for people on immunosuppressants.

Study	Result	People	Product
¹⁵	CD4 percentage rose, CD8 percentage fell and CD4/CD8 ratio improved versus Western medicine; numbers not given in the abstract.	Breast cancer patients with perimenopausal syndrome	Rehmannia-led Chinese herbal formulas (combination)

¹⁵

●

Bone mineral density and bone turnover (beta-CTX, SOST)

No clear change in trials

Bone density measured by DXA and blood markers of bone breakdown (beta-CTX) and bone cell signalling (SOST).

Very low certainty

Results and what it means

Why it was measured

Used to judge osteoporosis treatment.

Statistical vs. clinical meaning

Similar to a bone drug; no placebo group, so the change cannot be credited to the decoction.

Safety implication

Do not stop bone medicine.

Study	Result	People	Product
²⁹	Bone density rose in both groups after one year; after treatment the groups did not differ (femoral neck P=0.294; lumbar spine P=0.478). Beta-CTX fell and SOST rose in both.	72 adults with primary osteoporosis	Dihuang Decoction (combination) vs alendronate

²⁹

Safety

What studies and official sources say about side effects, medicines and who should check first. Each point shows what kind of evidence it comes from.

Main points to know 5

Almost all safety data are for formulas, not rehmannia alone. Human studies tested mixtures such as Liuwei Dihuang, Zhibai Dihuang and Si Wu Tang. Reviews report mostly mild events and no severe reactions, but adverse events were reported in only 6 of 11 trials in one 2026 review. No dedicated safety trial of rehmannia alone was found, and the cited reference pages give little detail. Systematic review ^{4 6 15 2}
Stomach and gut effects. A drug-reference page lists diarrhea and abdominal bloating. An herbal database lists stomach upset or dizziness and advises avoiding it with weak digestion, poor appetite or severe diarrhea. These are reference-page statements without cited studies, not trial results. Authoritative guidance ^{26 9}
Raw and prepared root are different products. Steaming or wine-processing changes the chemistry (iridoid glycosides fall, other compounds rise) and in mice changes effects on clotting and blood counts. Do not assume safety or effects of one form carry over to the other. Animal research ^{8 17}
Medicine interactions are mostly theoretical. One herbal database says rehmannia may interact with immunosuppressants, diuretics and corticosteroids but gives no mechanism or study. A drug-reference page lists no interactions and says its list is incomplete. No human interaction study was found. Formulas have been added to diabetes drugs and steroids in trials run by doctors. Authoritative guidance ^{9 26}
Pregnancy, breastfeeding and children. Reference pages say there is no or insufficient information for pregnancy and breastfeeding, and a monograph says no safe or effective dose is established for children. Ask a clinician first. Authoritative guidance ^{26 9 24}

Side effects 5

Effect	How often	Severity and recovery	Evidence
Diarrhea and abdominal bloating Listed by a drug-reference page. No frequency was found. The page says the list may be incomplete.	Not established	mild Not stated	Authoritative guidance ²⁶
Stomach upset or dizziness From an herbal database; no study or frequency given.	Not established	mild Not stated	Authoritative guidance ⁹
Adverse events in kidney-disease trials of Liuwei Dihuang Authors say reporting was incomplete.	12/287 (4.2%) formula vs 12/277 (4.3%) control, in the 6 of 11 trials that reported events	mild to moderate Not stated	Meta-analysis ⁴
Adverse events in a 48-week kidney trial Eighty-five events in 50 participants in total; types are not in the abstract.	22 participants (31%) in the add-on group vs 28 (36%) in the control group (as printed in the abstract)	Not stated Not stated	Controlled trial ²
Higher blood pressure rise in a Si Wu Tang analysis Systolic/diastolic rose about 11.4/8.4 mm Hg with the formula vs 6.4/2.9 with placebo in a post-hoc analysis of 76 young women; the authors found no strong significance and the finding is exploratory.	Not established	Not stated Not stated	Controlled trial ³²

Liver

We found no case report of liver injury from rehmannia. A search for a LiverTox entry did not find one (not confirmed absent). A 2015 review of liver injury from Chinese herbs established causality for 28 herbs or mixtures; rehmannia (Di Huang) is not among the names listed in its abstract, but we read only the abstract. A reference-page snippet says the root is contraindicated in chronic liver disease; we could not read that page, so this is NOT verified. Animal studies on catalpol and other compounds report liver protection, but that is not human proof. ^{28 25 1}

How often. No frequency could be given. Not finding reports is not proof of safety, and most human data are from formulas.

Monitoring. No agency monitoring advice was found. Stop and seek care for yellow skin or eyes, dark urine or unusual tiredness.

This is a safety connection. It is not evidence that Rehmannia (Di Huang) supports liver health.

Medicines and supplements 6

With	Why it matters	Importance	Evidence	What to do
Diabetes medicines and insulin prescription	Formulas lowered blood sugar when added to diabetes drugs in trials, and catalpol lowers blood sugar in animals. Added blood-sugar lowering is possible.	Unknown. Meta-analyses of add-on trials report lower fasting glucose; the abstracts do not report low blood sugar events.	Meta-analysis Very low certainty ^{23 18 1}	Tell your prescriber or pharmacist if you use rehmannia or a formula. Check blood sugar more often if you start it.
Blood pressure medicines and diuretics prescription	One herbal database says rehmannia may interact with diuretics; a review claims the root helps high blood pressure, but its data are weak; a Si Wu Tang analysis saw blood pressure rise more than placebo.	Unknown. Evidence points in different directions, and none is from rehmannia alone.	Authoritative guidance Not enough evidence ^{9 14 32}	Ask a doctor if you take blood pressure medicines or water pills; check your pressure.
Blood thinners and antiplatelet drugs prescription	In mice, raw root extract reduced clotting in a thrombosis model without changing clotting times (PT, APTT). No human data.	Unknown. Mouse data only.	Animal research Not enough evidence ⁸	Tell your prescriber. Raw and prepared root may differ.
Corticosteroids and immunosuppressants prescription	One herbal database lists them without a mechanism. In lupus trials, rehmannia formulas were added to steroids under medical supervision and steroid doses were reduced, but these were not interaction studies.	Unknown.	Authoritative guidance Not enough evidence ^{9 3 16}	Never change steroid or immunosuppressant doses on your own; tell the prescriber.
Other herbs and supplements that lower blood sugar (for example bitter melon or berberine) supplement	Additive effect in theory.	Unknown; no study.	Pharmacological theory Not enough evidence ¹	Mention all supplements to your pharmacist.
Liver-processed drugs (CYP enzymes) prescription	No human study of enzyme effects was found.	Not studied.	Pharmacological theory Not enough evidence	No advice beyond telling your pharmacist.

Who should check first 5

Situation	Advice	Evidence
Allergy to rehmannia	Avoid it. The drug-reference page lists hypersensitivity as the contraindication.	Authoritative guidance ²⁶
Weak digestion, poor appetite or diarrhea	An herbal database advises caution or avoidance, citing the traditional concept of spleen deficiency. This is traditional guidance.	Traditional use ⁹
Pregnancy and breastfeeding	Insufficient or no information; ask a clinician before use.	Authoritative guidance ^{26 9}
Children	No proven safe or effective amount is established.	Authoritative guidance ²⁴
Chronic liver or digestive disease	A garden-database snippet attributed to a WHO-based summary says it is contraindicated; NOT verified because the page could not be read.	Authoritative guidance ²⁵

Overdose, product quality and regulators

Summary. No acute toxicity of the root was found in the sources read. A 2022 review calls the root non-toxic in Chinese medicine, but this is the authors' statement, not a safety trial. Catalpol is described as well tolerated in animals. No overdose case was found. 'Chinese foxglove' is only a nickname; we found no report that the root contains heart-active digitalis compounds, and we did not research that point. NOT verified.

Animal. Catalpol is described as well tolerated in animal models at doses up to 200 mg/kg in efficacy studies (not a formal toxicity study).

Human doses studied. Formula doses and durations varied; a 48-week kidney trial is the longest controlled exposure found. Amounts are not given here; ask a doctor or pharmacist.

High dose or long term signals. None identified; no chronic toxicity study of the root was found.

Overdose response. No human overdose case found.

Genotoxicity. Not found.

Toxic plant parts. The root is the part used. Leaf extract was tested once for acne. Toxicity of other parts was not found.

Quality varies. Studies show the root can carry heavy metals, pesticides and microplastics, and processing changes its chemistry. We found no adulteration survey of retail products.

Microplastics and heavy metals. A 2025 study of eight rhizome herbs from a mulch-planting area found microplastics (20.83 to 43.65 items per gram) and heavy metals (arsenic, lead, chromium most linked to plastics); estimated daily intake was higher for Rehmannia glutinosa than most others. ³⁰

Pesticides and metals. A method paper removes 12 organochlorine pesticides and seven heavy metals from the root, showing they are a recognised concern. The abstract gives no market survey. ³³

Different processing, different product. Nine-cycle rice-wine processing changed iridoid glycosides and other compounds and effects in mice. ⁸

Adulteration. No adulteration report for rehmannia was found.

Body	Action	Date

When to get medical help

Swelling of the face, lips or throat, trouble breathing or hives: get emergency care.
Yellow skin or eyes, dark urine or severe tiredness: stop and see a doctor.
Severe or lasting diarrhea or belly bloating: stop and speak to a clinician.
Shaking, sweating or confusion from low blood sugar if you take diabetes medicines: treat and call your care team.

Stop the supplement and contact a clinician or emergency service. In the US, Poison Control is 1-800-222-1222.

General information only, not medical advice. Ask a clinician or pharmacist before use, especially with medicines, in pregnancy or with a health condition. See the Natural Remedy Safety guide.

Frequently asked questions

What is rehmannia?

Rehmannia glutinosa is a Chinese plant whose root is a major herb in Chinese medicine. It is used raw (sheng di huang) or steamed and prepared (shu di huang). Most research is on multi-herb formulas that contain it.

^{17 5}

What is the difference between raw and prepared rehmannia?

They are the same plant but different products. Steaming or wine-processing changes the chemistry: iridoid glycosides fall and other compounds rise. In mice, raw root reduced clotting more and prepared root improved blood counts more. Do not assume results for one apply to the other.

^{8 17}

Does rehmannia help diabetic kidney disease?

Meta-analyses of Chinese trials report lower urine albumin when formulas such as Liuwei Dihuang are added to standard care, but the trials are low quality. One Hong Kong trial found slower decline in kidney filtering and no significant change in urine albumin. No trial tests rehmannia alone.

^{4 2 18}

What is Liu Wei Di Huang Wan?

It is a six-herb Chinese formula led by prepared rehmannia. Studies of it are studies of the combination, so the effect cannot be credited to rehmannia alone.

^{4 23}

What is catalpol?

Catalpol is a compound in the root that is the focus of drug-like research. It has been studied in animals for diabetes and nerve protection, and in rats for how it is absorbed and cleared. No human trial of catalpol was found.

^{1 7}

Does it lower blood sugar?

Add-on trials of Liuwei Dihuang with diabetes drugs report small glucose improvements, but quality is low and HbA1c results disagree. Animal studies of catalpol report lower sugar. If you take diabetes medicines, talk to your prescriber first.

^{23 18 1}

Is there evidence for arthritis, osteoporosis or anemia?

For rheumatoid arthritis no trial was found. For osteoporosis, one small trial found a rehmannia decoction similar to alendronate, with no placebo. For anemia, a Si Wu Tang analysis showed no difference from placebo in anemia markers, and a monograph rates adjunct use in aplastic anemia as preliminary.

^{29 32 24}

What are the side effects?

Reference pages list diarrhea and abdominal bloating, and stomach upset or dizziness. Trials of formulas report mostly mild events, though reporting was incomplete. Rehmannia alone has not been tested in safety trials.

^{26 9 4}

Does it interact with medicines?

Interactions are mostly theoretical. One database lists immunosuppressants, diuretics and steroids without a mechanism. Extra blood-sugar lowering with diabetes drugs is possible. Mouse work suggests raw root may reduce clotting. No human interaction study was found, so tell your doctor or pharmacist.

^{9 23 8}

Is it safe in pregnancy or breastfeeding, or for children?

Not established. Reference pages say information is insufficient or unavailable, and a monograph says no safe or effective amount is known for children.

^{26 24}

Can it harm the liver or kidneys?

We found no case of liver injury, but we also found no LiverTox entry (not confirmed absent). Formulas were studied in kidney disease without a clear safety signal in the abstracts. People with liver or kidney disease should ask their doctor.

^{28 2}

Is it regulated or approved anywhere?

It is listed in the Chinese Pharmacopoeia and sold as a US dietary supplement. We did not find an EMA/HMPC monograph, an NCCIH page, a LiverTox entry or a WHO monograph (not confirmed absent). Contamination with heavy metals, pesticides or microplastics has been reported in studies.

^{24 30}

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Editorial transparency

Written by: AlternativeMed editorial team. Research compiled with AI assistance, then checked against PubMed records.
Medical review: None. This page has not been reviewed by a physician or pharmacist.
First published: 2026-10-25
Last substantive update: 2026-10-25
How we research: We searched PubMed, read abstracts, checked GBIF, NCBI Taxonomy and PubChem, and read the Restorative Medicine monograph, an RxList page and Hobbs database. We could not find EMA/HMPC, NCCIH, LiverTox, LactMed or WHO entries; these are marked not found, not confirmed absent. A Royal College of Physicians garden snippet could not be read and is unverified. Certainty ratings are the compiler's own reading. No study is cited that we could not verify.
How we rate evidence: See "How we rate evidence" in the Evidence tab.
Independence: No product is promoted on this page. No affiliate links are shown. If one is added later it will be labelled and kept apart from the evidence.

Sources 33

Each source was opened and checked. Where we read only the abstract, it says so. The small numbers in the text point here.

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Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.