Herbs & Botanicals · Chinese herb for upset stomach
Korean Mint
Agastache rugosa · also called Huo xiang, kwakhyang, Korean mint
Korean mint is an aromatic mint-family herb used in Chinese and Korean medicine for nausea, upset stomach and summer-damp complaints. Most human trials tested a many-herb formula that uses a different plant also called huo xiang, so they say little about Korean mint itself. Its oil is mostly estragole, which regulators treat with caution. The key caution: avoid the oil, and ask a doctor first if you are pregnant or breastfeeding.
General information, not medical advice. Last substantive update · Not medically reviewed. A named clinician has not signed off on this page. How this page is made
About Korean Mint
Korean mint (huo xiang, Agastache rugosa) is a traditional stomach herb. Human evidence is thin: the trials mostly tested a many-herb formula whose huoxiang is a different plant, patchouli. The oil is rich in estragole, which regulators handle with caution.
What it is
Korean mint is the aerial part of Agastache rugosa, a mint-family plant native to East Asia. Its leaves are eaten in Korean cooking and the dried herb is used in Chinese and Korean medicine.
Two plants share the name huo xiang. Huo xiang usually means Agastache rugosa. Guang huo xiang means Pogostemon cablin, patchouli. They look alike dried but have different chemistry, and a Korean food-safety case describes them being mixed up.
What the research shows
The best human trial, in 212 adults with IBS and diarrhea, tested the Huoxiang Zhengqi formula and found more adequate relief than placebo. A small trial found a higher no-vomiting rate when the formula was added to chemotherapy anti-nausea drugs. Both tested a formula, not Korean mint.
The only trial of Agastache rugosa extract itself was a 45-person skin-aging study by the product makers. Everything else on the plant is lab or animal work.
At a glance
Traditional uses history, not proof
- Nausea and upset stomach
- Summer-damp digestive complaints
- Leaf used as a flavouring in Korean cooking
Studied for research
- IBS with diarrhea (formula), low
- Nausea after chemotherapy (formula), very low
- Acute stomach and bowel infection (formula), very low
- Stomach complaints (the plant itself), insufficient
- Skin aging (extract), very low
- Mild eczema (formula), very low
- COVID-19 (formula), insufficient
- Brain waves from the scent, insufficient
Main compounds
- Estragole (main oil component in one sample)
- Tilianin
- Rosmarinic acid
- Apigenin and acacetin
- Pogostone (found in patchouli, not shown for Korean mint)
Common forms
- Dried herb (decoction)
- Leaf as food
- Essential oil (not for swallowing)
- Branded extract tablets
- Multi-herb formulas (oral liquid, pills)
Research links: EMA: estragole public statement (2005) · IBS-D formula trial, 2025 (PubMed) · Chemotherapy nausea formula trial, 2023 (PubMed) · Agastache review, 2023 (PubMed) · Skin-aging extract trial, 2026 (PubMed) · Estragole in human liver cells, 2026 (PubMed) · Research Library · Genes & Biomarkers Library
The plant and its history
- Accepted scientific name
- Agastache rugosa (Fisch. & C.A.Mey.) Kuntze
- Naming authority
- GBIF accepted name, usageKey 7307327 (match confidence 99, checked 2026-10-25).
- Common names
- Korean mint (English); Huo xiang (藿香) (Chinese (pinyin)); Kwakhyang (Korean)
- Botanical family
- Lamiaceae (mint family)
- Classification
- Plantae > Lamiales (GBIF) > Lamiaceae (GBIF) > Agastache > Agastache rugosa
- Native range
- East Asia (stated in the 2023 Agastache review; the rest of the genus is North American).
- Habitat
- Not verified from a source read.
- What the plant looks like
- Roots: Not verified.; Stems: Not verified.; Leaves: Leaves are aromatic and eaten in Korean cooking.; Flowers: Not verified.; Fruit: Not verified.
- Cultivation
- Not verified.
- Harvest and processing
- Aerial parts are used dried (decoction) or fresh as food; essential oil is steam-distilled.
- Look-alikes and adulterants
- Name: Patchouli (Pogostemon cablin), guang huo xiang; Note: Another plant called huo xiang; dried herbs look alike and a Korean case describes mix-ups. Chemistry differs (patchouli alcohol and pogostone vs estragole-rich oil).; Name: Anise hyssop (Agastache foeniculum); Note: A North American relative also rich in estragole; the EMA table lists it, not A. rugosa, in the 2014 draft.
- Sustainability and conservation
- Not assessed here.
Traditional use and history history, not clinical proof
| Tradition or era | Documented use | Source |
|---|---|---|
| Traditional Chinese and Korean medicine | Aerial parts used for stomach and bowel complaints, nausea and summer-damp patterns (as described in recent Chinese research papers and trial protocols; the ancient texts were not read). | p39854932 |
| Korean cooking | Leaves used in salads and soups for aroma and taste. | s-pmc9311756-eeg |
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 |
|---|---|---|---|---|
| Estragole (methyl chavicol) PubChem 8815 | phenylpropanoid (alkenylbenzene) | Aerial parts | Main oil component in one sample (89.49%); a genotoxic carcinogen in animals per the EMA. 21 4 1 20 | Laboratory research |
| Tilianin PubChem 5321954 | flavonoid glycoside | Aerial parts | Listed as a possible gut-motility marker in a lab and zebrafish study. 10 | Laboratory research |
| Rosmarinic acid PubChem 5281792 | phenolic acid | Aerial parts | Listed as a possible gut-motility marker; lab and zebrafish work only. 10 | Laboratory research |
| Pogostone PubChem 54695756 | ketone (patchouli-type) | Aerial parts | Reported in patchouli (Pogostemon cablin) leaves; not shown in our sources for Agastache rugosa. 14 | Laboratory research |
| Limonene and beta-caryophyllene | monoterpene and sesquiterpene | Aerial parts | Minor oil components (limonene 3.40% in one sample). 11 21 | Laboratory research |
Mechanisms, receptors and pathways
| Target or pathway | Gene or receptor | What was found | Level |
|---|---|---|---|
| Stomach inflammation pathways (predicted) | AKT1, NFKBIA, MAPK3 (computer prediction) | In mice an extract relieved stomach-lining damage; computer analysis linked acacetin and luteolin to these genes. 18 | Animal research |
| Estragole activation in the liver | CYP1A2, SULT1A1 | Human liver cells activate estragole through these enzymes; damage needs a threshold level of DNA adducts. 1 2 | Laboratory research |
| Brain electrical activity | Not identified | Inhaled oil changed EEG theta and alpha measures in 38 adults. 21 | Human data |
Absorption, metabolism and elimination
- Absorption
- No human absorption study of Agastache rugosa compounds was found.
- Distribution
- Not studied.
- Metabolism
- Estragole is activated in liver by CYP1A2 and sulfotransferases (lab and animal).
- Elimination
- Not studied for Korean mint.
- Bioavailability
- Not known.
Isolated compounds versus whole extracts
The only single-plant trial used a branded extract. Most trials used a multi-herb formula. Tea, decoction and oil have not been compared in people.
Nutritional composition
Leaves are eaten as a flavouring in Korean cooking; no nutrient claim is made here.
1 low certainty4 very low certainty4 not enough evidence
What is Korean Mint good for?
The proposed uses and how strong the human evidence is for each. Most trials tested a multi-herb formula, not Korean mint alone.
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.
Diarrhea-type irritable bowel syndrome (formula)
Low certaintyIn one 212-person trial in China, more people on the Huoxiang Zhengqi oral liquid reported adequate relief of IBS with diarrhea than on placebo after 4 weeks. It is a many-herb formula whose huoxiang is Pogostemon cablin, so this does not show that Korean mint works alone.
3 studiesMost trials used Huoxiang Zhengqi, a multi-herb Chinese patent medici…
Studies, doses and limits
What the trials found
One multicenter double-blind trial (14 hospitals, 108 formula vs 104 placebo, 4 weeks). The responder rate was higher with the formula, and the symptom severity score fell more. No serious adverse events were reported.
Results
More adequate-relief responders than placebo
Effect sizes as reported
Rate difference 0.29 (95% CI 0.14 to 0.43); severity score mean difference -10.92 (95% CI -18.93 to -2.90).
Why this rating
One well-run trial of a formula; short; the plant named huoxiang in the formula is probably not Korean mint.
Form and dose studied
Most trials used Huoxiang Zhengqi, a multi-herb Chinese patent medicine (oral liquid, pills or dropping pills). Its huoxiang is listed as Pogostemon cablin in the trial protocol, so results are about the formula, not Korean mint. Amounts are not given here.
Who was studied
Adults 18-70 with IBS-D in China.
Limits
Single trial, 4 weeks, formula not single herb, abstract only.
Why researchers looked
Huoxiang Zhengqi is a well-known Chinese medicine for stomach and bowel upset, so researchers tested it in IBS-D.
Traditional use
In Chinese medicine the formula is used for gut complaints with 'dampness' patterns.
Proposed mechanism Laboratory research
Not shown in people. Lab work on Agastache rugosa suggests gut-related compounds (rosmarinic acid, tilianin, apigenin, acacetin) but this is prediction and zebrafish work.
A proposed mechanism does not show that the effect happens in people.
No serious adverse events in the trial; see the Safety tab.
Nausea and vomiting after chemotherapy (formula, added to standard drugs)
Very low certaintyIn a small trial of 60 patients having cisplatin chemotherapy, more people had no vomiting and no rescue medicine when the Huoxiang Zhengqi oral liquid was added to standard anti-nausea drugs than when a placebo was added. It does not replace prescribed anti-nausea treatment.
1 studiesMost trials used Huoxiang Zhengqi, a multi-herb Chinese patent medici…
Studies, doses and limits
What the trials found
An exploratory multicenter trial (60 people). Complete response in the acute phase was 63.33% vs 33.33% (p = 0.020), and beyond the risk phase 96.67% vs 46.67%. Days without nausea or vomiting were higher in the formula group.
Results
Higher complete-response rate when added to standard drugs
Effect sizes as reported
63.33% vs 33.33% (acute); 96.67% vs 46.67% (delayed); days with no nausea or vomiting 18.10 vs 12.13.
Why this rating
Small exploratory trial of a formula; adverse events and funding not in the abstract.
Form and dose studied
Most trials used Huoxiang Zhengqi, a multi-herb Chinese patent medicine (oral liquid, pills or dropping pills). Its huoxiang is listed as Pogostemon cablin in the trial protocol, so results are about the formula, not Korean mint. Amounts are not given here.
Who was studied
People having multiday cisplatin chemotherapy who could not use NK1-antagonist drugs.
Limits
Only 60 people; abstract only; not about the single herb. Tell your oncology team about any herbal product.
Why researchers looked
Huoxiang Zhengqi is traditionally used for nausea and vomiting, so it was tried alongside standard drugs.
Traditional use
Used in Chinese medicine for nausea and a heavy, queasy stomach.
Proposed mechanism Pharmacological theory
Not studied in this trial.
A proposed mechanism does not show that the effect happens in people.
Chemotherapy patients should check any herb with their cancer team first.
Acute stomach and bowel infection (formula, with usual treatment)
Very low certaintyA 2019 review of 44 mostly low-quality Chinese trials found a better 'effective rate' when the Huoxiang Zhengqi pills were added to usual treatment, and better fever relief. The authors say better research is needed.
1 studiesMost trials used Huoxiang Zhengqi, a multi-herb Chinese patent medici…
Studies, doses and limits
What the trials found
Meta-analysis of 44 randomized trials with 4,153 patients. The pills plus usual treatment beat usual treatment alone on total effective rate and fever relief; adverse reactions did not differ statistically. Overall study quality was low.
Results
Better effective rate in low-quality trials
Effect sizes as reported
Numbers per outcome not in the abstract.
Why this rating
The reviewers rated the included studies low in quality.
Form and dose studied
Most trials used Huoxiang Zhengqi, a multi-herb Chinese patent medicine (oral liquid, pills or dropping pills). Its huoxiang is listed as Pogostemon cablin in the trial protocol, so results are about the formula, not Korean mint. Amounts are not given here.
Who was studied
People with acute gastroenteritis in China.
Limits
Low-quality trials, Chinese-language review, abstract only.
Why researchers looked
The pills are widely used in China for summer stomach upsets.
Traditional use
Traditional use for summer-damp stomach and bowel complaints.
Proposed mechanism Pharmacological theory
Not studied.
A proposed mechanism does not show that the effect happens in people.
No statistical difference in adverse reactions versus usual care in this review.
Stomach and bowel complaints (traditional use of the plant)
Not enough evidenceKorean mint (Agastache rugosa) is described as a traditional food and medicine often used for gut-motility problems, and huo xiang is used in Chinese medicine for nausea and summer-damp stomach upset. No trial of the single plant for these uses was found.
3 studiesA. rugosa herb (aerial parts); preparations not compared.
Studies, doses and limits
What the trials found
No human trial of Agastache rugosa for stomach or bowel complaints was found.
Results
Not tested in people
Effect sizes as reported
Not applicable
Why this rating
Rated on tradition and lab work only.
Form and dose studied
A. rugosa herb (aerial parts); preparations not compared.
Who was studied
Not tested.
Limits
No human data; lab results may not carry over.
Why researchers looked
Long traditional use in China and Korea drives the lab research.
Traditional use
Used in China and Korea as a stomach-settling aromatic herb; leaves are also eaten in Korean cooking.
Proposed mechanism Animal research
In mice, an A. rugosa extract relieved stomach-lining damage; computer analysis points to acacetin and luteolin. Chemical work picked rosmarinic acid, tilianin, apigenin and acacetin as possible markers. All of this is lab or animal work.
A proposed mechanism does not show that the effect happens in people.
See the Safety tab: the oil is very rich in estragole.
Skin aging (Agastache rugosa extract tablets)
Very low certaintyIn a 45-person 12-week trial, a branded Agastache rugosa extract and a three-plant complex both gave smaller wrinkles and less water loss through the skin than placebo. The makers were involved and no other trial has repeated it.
1 studiesBranded A. rugosa extract tablets (Agatri) and a complex with fig and…
Studies, doses and limits
What the trials found
Randomized double-blind trial: extract, complex or placebo for 12 weeks. At 8 and 12 weeks wrinkle size and transepidermal water loss were lower than placebo; moisture, density and elasticity also improved.
Results
Smaller wrinkles and less skin water loss
Effect sizes as reported
Statistics for each outcome are not in the abstract.
Why this rating
One small trial by product makers; abstract lacks numbers.
Form and dose studied
Branded A. rugosa extract tablets (Agatri) and a complex with fig and goji extracts; aerial-part use not stated in the abstract.
Who was studied
45 participants; skin-aging features.
Limits
Small, industry-linked, abstract only, adverse events not stated.
Why researchers looked
Lab work suggested the extract protects skin; this trial tested it in people.
Traditional use
Not a traditional use.
Proposed mechanism Preliminary mechanism
Preclinical work suggested effects on collagen and hyaluronic acid (per the abstract); not tested here.
A proposed mechanism does not show that the effect happens in people.
Adverse events not stated in the abstract.
Mild eczema (formula)
Very low certaintyIn a 218-person, 4-week trial in China, a skin score fell slightly more with Huoxiang Zhengqi oral liquid than with placebo. Only mild disease was studied.
1 studiesMost trials used Huoxiang Zhengqi, a multi-herb Chinese patent medici…
Studies, doses and limits
What the trials found
Adjusted EASI difference at week 4 was -0.44 (95% CI -0.83 to -0.04; p = 0.033). At week 8, 66% vs 50.5% had at least a 50% EASI reduction (p = 0.022).
Results
Small average skin-score difference
Effect sizes as reported
-0.44 EASI points (95% CI -0.83 to -0.04)
Why this rating
Tiny average difference, short trial, formula.
Form and dose studied
Most trials used Huoxiang Zhengqi, a multi-herb Chinese patent medicine (oral liquid, pills or dropping pills). Its huoxiang is listed as Pogostemon cablin in the trial protocol, so results are about the formula, not Korean mint. Amounts are not given here.
Who was studied
Adults with mild atopic dermatitis or eczema.
Limits
Only mild disease; 4 weeks; abstract only.
Why researchers looked
The formula is used in China for skin and gut 'dampness' problems.
Traditional use
Traditional dampness-pattern use.
Proposed mechanism Pharmacological theory
Not studied.
A proposed mechanism does not show that the effect happens in people.
Not detailed in the abstract.
COVID-19 (formula)
Not enough evidenceIn a 283-patient trial, symptom improvement did not differ significantly between groups. There is no good evidence of benefit.
1 studiesMost trials used Huoxiang Zhengqi, a multi-herb Chinese patent medici…
Studies, doses and limits
What the trials found
Three groups for 14 days. No significant difference in symptom improvement or in progression to severe disease.
Results
No significant difference in the main result
Effect sizes as reported
Severe disease 1.6% vs 8.6% vs 11.1% (not significant).
Why this rating
The main result was null; the arm combined two formulas.
Form and dose studied
Most trials used Huoxiang Zhengqi, a multi-herb Chinese patent medicine (oral liquid, pills or dropping pills). Its huoxiang is listed as Pogostemon cablin in the trial protocol, so results are about the formula, not Korean mint. Amounts are not given here.
Who was studied
COVID-19 patients, 2020.
Limits
The positive conclusion in the abstract goes beyond the null result.
Why researchers looked
Used in China during the 2020 outbreak.
Traditional use
Traditional use for dampness-type fever and nausea.
Proposed mechanism Pharmacological theory
Not studied.
A proposed mechanism does not show that the effect happens in people.
Not detailed.
Brain-wave response to the scent of the oil
Not enough evidenceIn 38 healthy adults, smelling a diluted Korean mint oil changed several brain-wave (EEG) measures. No mood, sleep or thinking test was measured, so this is not a proven benefit.
1 studiesInhaled A. rugosa essential oil; the sample was 89.49% estragole.
Studies, doses and limits
What the trials found
Single-group exposure study. Theta power fell and alpha-type measures rose during exposure compared with no odor.
Results
Brain-wave measures changed
Effect sizes as reported
Not applicable (no health outcome)
Why this rating
Single-group design; EEG is a marker, not a symptom.
Form and dose studied
Inhaled A. rugosa essential oil; the sample was 89.49% estragole.
Who was studied
38 healthy adults, South Korea.
Limits
Small, no control for expectation, oil composition varies.
Why researchers looked
Researchers asked whether the aroma affects the brain.
Traditional use
Leaves are used in Korean cooking for aroma.
Proposed mechanism Preliminary mechanism
Not known.
A proposed mechanism does not show that the effect happens in people.
The oil is mostly estragole; do not swallow it.
Cavity-related bacteria (laboratory only)
Not enough evidenceIn a lab dish the oil slowed growth and acid production of one cavity-related bacterium. It was not tested in the mouth.
1 studiesEssential oil only.
Studies, doses and limits
What the trials found
No human data.
Results
Not tested in people
Effect sizes as reported
Inhibition from 0.02 mg/mL in a dish
Why this rating
Laboratory only.
Form and dose studied
Essential oil only.
Who was studied
None.
Limits
Lab only.
Why researchers looked
Oral bacteria are a common test target for plant oils.
Traditional use
Not a traditional use.
Proposed mechanism Laboratory research
Lab results on Streptococcus mutans.
A proposed mechanism does not show that the effect happens in people.
Not for swallowing; see the Safety tab.
Connections to the rest of health
How Korean Mint 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
A. Wellness goals
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Digestive Support | Demonstrated clinical effect | Low certainty | Diarrhea-type irritable bowel syndrome (formula): In one 212-person trial in China, more people on the Huoxiang Zhengqi oral liquid reported adequate relief of IBS with diarrhea than on placebo after 4 weeks. It is a many-herb formula whose huoxiang is Pogostemon cablin, so this does not show that Korean mint works alone. | 9 22 10 |
| Gut Health | Demonstrated clinical effect | Low certainty | Diarrhea-type irritable bowel syndrome (formula): In one 212-person trial in China, more people on the Huoxiang Zhengqi oral liquid reported adequate relief of IBS with diarrhea than on placebo after 4 weeks. It is a many-herb formula whose huoxiang is Pogostemon cablin, so this does not show that Korean mint works alone. | 9 22 10 |
| Digestive Support | Potential benefit | Very low certainty | Nausea and vomiting after chemotherapy (formula, added to standard drugs): In a small trial of 60 patients having cisplatin chemotherapy, more people had no vomiting and no rescue medicine when the Huoxiang Zhengqi oral liquid was added to standard anti-nausea drugs than when a placebo was added. It does not replace prescribed anti-nausea treatment. Acute stomach and bowel infection (formula, with usual treatment): A 2019 review of 44 mostly low-quality Chinese trials found a better 'effective rate' when the Huoxiang Zhengqi pills were added to usual treatment, and better fever relief. The authors say better research is needed. | 23 26 |
| Gut Health | Potential benefit | Very low certainty | Acute stomach and bowel infection (formula, with usual treatment): A 2019 review of 44 mostly low-quality Chinese trials found a better 'effective rate' when the Huoxiang Zhengqi pills were added to usual treatment, and better fever relief. The authors say better research is needed. | 26 |
| Digestive Support | Traditional use | Not enough evidence | Stomach and bowel complaints (traditional use of the plant): Korean mint (Agastache rugosa) is described as a traditional food and medicine often used for gut-motility problems, and huo xiang is used in Chinese medicine for nausea and summer-damp stomach upset. No trial of the single plant for these uses was found. | 10 18 19 |
| Healthy Skin | Potential benefit | Very low certainty | Skin aging (Agastache rugosa extract tablets): In a 45-person 12-week trial, a branded Agastache rugosa extract and a three-plant complex both gave smaller wrinkles and less water loss through the skin than placebo. The makers were involved and no other trial has repeated it. Mild eczema (formula): In a 218-person, 4-week trial in China, a skin score fell slightly more with Huoxiang Zhengqi oral liquid than with placebo. Only mild disease was studied. | 3 25 |
| Healthy Aging | Potential benefit | Very low certainty | Skin aging (Agastache rugosa extract tablets): In a 45-person 12-week trial, a branded Agastache rugosa extract and a three-plant complex both gave smaller wrinkles and less water loss through the skin than placebo. The makers were involved and no other trial has repeated it. | 3 |
| Immune Support | Biological association | Not enough evidence | COVID-19 (formula): In a 283-patient trial, symptom improvement did not differ significantly between groups. There is no good evidence of benefit. | 24 |
| Mental Clarity | Preliminary mechanism | Not enough evidence | Brain-wave response to the scent of the oil: In 38 healthy adults, smelling a diluted Korean mint oil changed several brain-wave (EEG) measures. No mood, sleep or thinking test was measured, so this is not a proven benefit. | 21 |
| Digestive Support | Preliminary mechanism | Not enough evidence | Cavity-related bacteria (laboratory only): In a lab dish the oil slowed growth and acid production of one cavity-related bacterium. It was not tested in the mouth. | 11 |
B. Body systems
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Digestive System | Biological association | Low certainty | Studied for: Diarrhea-type irritable bowel syndrome (formula) Studied for: Nausea and vomiting after chemotherapy (formula, added to standard drugs) | 9 22 10 23 26 18 19 11 |
| Integumentary System | Biological association | Very low certainty | Studied for: Skin aging (Agastache rugosa extract tablets) Studied for: Mild eczema (formula) | 3 25 |
| Immune System | Biological association | Not enough evidence | Studied for: COVID-19 (formula) | 24 |
| Nervous System | Biological association | Not enough evidence | Studied for: Brain-wave response to the scent of the oil | 21 |
I. Biomarkers
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| IBS symptom severity score (IBS-SSS) | Biological association | Low certainty | Measured in trials: lowered. A lab change is not the same as a health benefit. | 9 |
| Complete response (no vomiting, no rescue medicine) | Biological association | Very low certainty | Measured in trials: raised. A lab change is not the same as a health benefit. | 23 |
| Total clinical effective rate | Biological association | Very low certainty | Measured in trials: raised. A lab change is not the same as a health benefit. | 26 |
| Wrinkle size and transepidermal water loss | Biological association | Very low certainty | Measured in trials: lowered. A lab change is not the same as a health benefit. | 3 |
| Eczema Area and Severity Index (EASI) | Biological association | Very low certainty | Measured in trials: lowered. A lab change is not the same as a health benefit. | 25 |
| EEG theta and alpha power | Biological association | Not enough evidence | Measured in trials: mixed. A lab change is not the same as a health benefit. | 21 |
J. Genes, receptors and enzymes
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| CYP1A2 / SULT1A1 (estragole activation) | Preliminary mechanism | In vitro | Lab finding in human liver cells. | 1 |
K. Biological pathways
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Brain wave activity (EEG) | Preliminary mechanism | Human | Changed on inhaling the oil in a small study. | 21 |
L. Active compounds
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Estragole | Authoritative guidance | Main component of the oil in the sample studied; the EMA calls it a genotoxic carcinogen in animals. Preparation or compound: Agastache rugosa essential oil |
4 21 | |
| Estragole (methyl chavicol) | Biological association | In vitro | Main oil component in one sample (89.49%); a genotoxic carcinogen in animals per the EMA. Preparation or compound: Aerial parts |
21 4 1 20 |
| Tilianin | Biological association | In vitro | Listed as a possible gut-motility marker in a lab and zebrafish study. Preparation or compound: Aerial parts |
10 |
| Rosmarinic acid | Biological association | In vitro | Listed as a possible gut-motility marker; lab and zebrafish work only. Preparation or compound: Aerial parts |
10 |
| Pogostone | Biological association | In vitro | Reported in patchouli (Pogostemon cablin) leaves; not shown in our sources for Agastache rugosa. Preparation or compound: Aerial parts |
14 |
| Limonene and beta-caryophyllene | Biological association | In vitro | Minor oil components (limonene 3.40% in one sample). Preparation or compound: Aerial parts |
11 21 |
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 6 lab markers
Tap a number to show only those markers. Counts are markers, not people.
The evidence
The research centre for Korean Mint. Every record here was checked against PubMed or the publisher's page; we never list a study we have not verified.
Evidence by outcome
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 started from our earlier evidence summary for huo xiang, re-checked PubMed records and abstracts, read the EMA estragole statements (2005 final and 2014 draft) and an open-access EEG paper, and checked plant names in GBIF and NCBI Taxonomy and compounds in PubChem. Not read: the revised EMA statement, EFSA opinion, NCCIH, LiverTox, LactMed, WHO and Chinese Pharmacopoeia entries, and the full texts of the formula trials. Certainty ratings are the compiler's reading.
Study library: every study we checked 26
| Study | Design | People | Product, dose, length | Result |
|---|---|---|---|---|
| Ackermann 2025 Molecular dosimetry of estragole and 1'-hydroxyestragole-induced DNA adduct formation, clastogenicity and cytotoxicity in human liver cell models. Arch Toxicol · PMID 40397106 · DOI |
Laboratory research in-vitro |
Human liver cell lines and primary human hepatocytes; rat hepatocytes | Estragole and its metabolite 1'-hydroxyestragole not applicable Lab exposures Lab experiments · vs Not applicable |
Estragole is activated by the liver enzymes CYP1A2 and SULT1A1. Chromosome damage appeared only at high lab concentrations (1 mM or more for estragole). The authors conclude a threshold level of DNA adducts is needed and is unlikely to be reached in humans by chronic phytomedicine or dietary exposure. Threshold-type response in human liver cells Methods, limits and fundingOutcomes: DNA adducts, chromosome damage, cell death Limitations: Abstract only. Lab cells; the conclusion is the authors' modelling. Funding and conflicts: No conflicts declared. Read: abstract |
| Ackermann 2026 Formation and persistence of estragole-derived DNA adducts in human liver cells and tissue. Arch Toxicol · PMID 41915187 · DOI |
Laboratory research in-vitro |
Human liver tissue samples and human liver cells | Estragole (pure compound) and a bitter fennel infusion not applicable Lab exposures Lab experiments · vs Not applicable |
Estragole-derived DNA adducts were found in many human liver samples, at levels the authors say are comparable to methyleugenol and well below those that cause mutations in cells. Repeated short exposure of human liver cells built up one adduct type. Fennel tea gave lower adduct levels than expected. Adducts detectable in human liver; below damaging levels in cells Methods, limits and fundingOutcomes: DNA adducts from estragole Limitations: Abstract only. Lab measurements, not cancer outcomes in people. Estragole, not Korean mint itself. Funding and conflicts: No conflicts declared. Read: abstract |
| Cho 2026 Comparative Effects of Agastache rugosa Extract and a Complex of Agastache rugosa, Ficus carica, and Lycium barbarum Extracts on Skin Aging: a randomized, double-blind, placebo-controlled trial. J Med Food · PMID 41817298 · DOI |
Controlled trial |
45 45 participants (skin aging) |
Agastache rugosa extract (branded Agatri), and a three-plant complex (AGEs Blocker) not stated in the abstract 1000 mg/day A. rugosa extract and 500 mg/day complex in the trial; trial amounts only, not advice 12 weeks · vs Maltodextrin tablets (placebo) |
At 8 and 12 weeks both the A. rugosa extract and the complex reduced wrinkle size and water loss through the skin compared with placebo; moisture, density and elasticity also improved. The complex did better than the extract alone. Smaller wrinkle size and less skin water loss vs placebo Methods, limits and fundingOutcomes: Wrinkle size, transepidermal water loss, skin moisture, dermal density, elasticity Limitations: Abstract only. Small trial; number per group and adverse events not in the abstract. Branded extracts; the complex contains two other plants. Funding and conflicts: Authors are from the product makers (COSMAX NS / COSMAX China) and declare no conflicts. Treat as industry-linked. Read: abstract |
| European Medicines Agency (HMPC) 2005 Public statement on the use of herbal medicinal products containing estragole (final, 23 November 2005) European Medicines Agency (HMPC) · Source |
Authoritative guidance |
Not applicable | Read 2026-10-25. Calls estragole a naturally occurring genotoxic carcinogen with DNA potency similar to safrole; lists Agastache rugosa essential oil at about 90% estragole; says exposure of young children, pregnant and breastfeeding women should be minimised. Methods, limits and fundingRead: full-text | |
| European Medicines Agency (HMPC) 2014 Public statement on the use of herbal medicinal products containing estragole, DRAFT revision 1 (24 November 2014) European Medicines Agency (HMPC) · Source |
Authoritative guidance |
Not applicable | Read 2026-10-25. Draft: short-term adult use at recommended amounts of herbal medicines is judged not to pose a significant cancer risk; still says exposure should be kept as low as practically achievable and minimised in young children and pregnant and breastfeeding women; proposes a limit for medicinal products. Its plant table lists A. foeniculum, not A. rugosa. A later revised statement exists (see s-fimea-estragole) and was not read. Methods, limits and fundingRead: full-text | |
| Fimea (Finnish Medicines Agency) 2024 Safety limits for medicinal products containing estragole have been revised Fimea (Finnish Medicines Agency) · Source |
Authoritative guidance |
Not applicable | Seen only as a web search summary, page not opened: says the HMPC published a revised estragole public statement with new guidance values for medicinal products. Numbers NOT read. Methods, limits and fundingRead: summary-only | |
| GBIF 2026 GBIF species match: Agastache rugosa (Fisch. & C.A.Mey.) Kuntze GBIF · Source |
Database record |
Not applicable | Checked 2026-10-25: accepted, exact match, confidence 99, family Lamiaceae, order Lamiales, usageKey 7307327. Methods, limits and fundingRead: full-text | |
| GBIF 2026 GBIF species match: Pogostemon cablin (Blanco) Benth. GBIF · Source |
Database record |
Not applicable | Checked 2026-10-25: accepted, exact match, confidence 99, family Lamiaceae, usageKey 2926672. Methods, limits and fundingRead: full-text | |
| Guo 2025 Huoxiang Zhengqi oral liquid for irritable bowel syndrome with diarrhea: a multicenter, double-blind, randomized controlled trial. Phytomedicine · PMID 41297321 · DOI |
Controlled trial |
212 Adults 18-70 with IBS-D, 14 hospitals in China (108 formula, 104 placebo) |
Huoxiang Zhengqi (HXZQ), a multi-herb Chinese patent medicine (oral liquid) multi-herb formula (not Korean mint alone) Trial amount not given here 4 weeks · vs Placebo |
Responder rate was higher with the formula (rate difference 0.29, 95% CI 0.14 to 0.43). The symptom severity score fell more (mean difference -10.92, 95% CI -18.93 to -2.90). No serious adverse events were reported. Higher adequate-relief rate than placebo at 4 weeks Methods, limits and fundingOutcomes: Adequate-relief responder rate; IBS symptom severity score Limitations: Abstract only. The formula's huoxiang is listed as Pogostemon cablin in the trial protocol (summary-only), so this is not evidence for Agastache rugosa. Short trial, China only. Funding and conflicts: Product supplied by the maker (Chongqing Taiji) with no role in design, analysis or reporting, per the authors. No competing interests declared. Read: abstract |
| Jiang 2025 Gastrointestinal motility modulation efficacy-related chemical marker findings and QAMS-based quality control of Agastache rugosa. J Pharm Biomed Anal · Source · DOI |
Laboratory research abstract |
Lab chemistry plus a zebrafish model; 26 commercial batches of A. rugosa measured | Agastache rugosa herb (commercial batches) aerial parts (as sold) Not applicable Not applicable · vs Not applicable |
Chemical markers for quality control; no human data Abstract only. Computer prediction plus zebrafish; no people. Describes A. rugosa as often used for gut-motility disorders. Methods, limits and fundingOutcomes: Nine compounds were screened as possible gut-motility-related markers; five (rosmarinic acid, tilianin, apigenin, acacetin, cirsimaritin) matched earlier literature; four were newly identified and tested in zebrafish. Limitations: Grant from a national Chinese research programme (one author); no competing interests stated. Funding and conflicts: in-vitro Read: https://pubmed.ncbi.nlm.nih.gov/39854932/ |
| Kim 2024 The Inhibitory Effect of Agastache rugosa Essential Oil on the Dental Biofilm. Molecules · PMID 39459275 · DOI |
Laboratory research in-vitro |
Laboratory culture of Streptococcus mutans | Agastache rugosa essential oil aerial parts (oil) Concentrations from 0.02 mg/mL in a lab dish Lab experiment · vs 0.1% sodium fluoride (positive control) |
Growth and acid production were significantly inhibited from 0.02 mg/mL; at 0.04 mg/mL the effect was similar to 0.1% fluoride. Main oil components were estragole, limonene and beta-caryophyllene. Slowed one cavity-related bacterium in a dish Methods, limits and fundingOutcomes: Bacterial growth, acid production, biofilm genes Limitations: Abstract only. Laboratory only; not tested in the mouth or in people. Funding and conflicts: No conflicts declared. Read: abstract |
| Korean Society of Crop Science 2022 DNA-based PCR to distinguish A. rugosa and P. cablin (conference abstract) Korean Society of Crop Science · Source |
Conference abstract |
Not applicable | From our earlier summary and a web search snippet; the PDF was not re-opened. Describes a 2022 Korean food-safety case where A. rugosa was sold as Kwakhyang without being told apart from P. cablin. Methods, limits and fundingRead: summary-only | |
| Liu 2025 Haplotype-resolved genome of Agastache rugosa (Huo Xiang) provides insight into monoterpenoid biosynthesis and gene cluster evolution. Hortic Res · PMID 40224328 · DOI |
Laboratory research in-vitro |
Plant genome study | Agastache rugosa (a monoterpene chemotype making pulegone and isomenthone) whole plant Not applicable Not applicable · vs Not applicable |
Describes a chemotype of A. rugosa that makes pulegone and isomenthone, showing that oil chemistry differs between plants. Chemotype evidence Methods, limits and fundingOutcomes: Genome and gene clusters Limitations: Abstract only. Plant genetics, no health data. Funding and conflicts: No conflicts declared. Read: abstract |
| Mrisho 2025 Unlocking the Therapeutic Potential of Patchouli Leaves: A Comprehensive Review of Phytochemical and Pharmacological Insights. Plants (Basel) · PMID 40219102 |
Narrative review in-vitro |
Review of Pogostemon cablin (patchouli) | Pogostemon cablin leaf and oil leaf Not applicable Not applicable · vs Not applicable |
Patchouli leaves contain patchouli alcohol, beta-patchoulene, pogostone, alpha-bulnesene and beta-caryophyllene. Reported effects are lab-type; the authors call for validation. Chemistry; not Agastache Methods, limits and fundingOutcomes: Chemistry and pharmacology Limitations: Abstract only. This is the other plant called huo xiang (guang huo xiang). Funding and conflicts: No conflicts declared. Read: abstract |
| NCBI 2026 NCBI Bookshelf title search (LiverTox / LactMed) for Agastache, huoxiang, patchouli, estragole NCBI · Source |
Database record |
Not applicable | A single combined title search on 2026-10-25 returned unrelated-looking hits and no chapter was opened or confirmed for Agastache rugosa. Treat as: no LiverTox or LactMed entry confirmed. Methods, limits and fundingRead: summary-only | |
| NCBI 2026 NCBI Taxonomy: Agastache rugosa NCBI · Source |
Database record |
Not applicable | Search returned taxonomy id 39271 (checked 2026-10-25). Methods, limits and fundingRead: full-text | |
| NCBI 2026 NCBI Taxonomy: Pogostemon cablin NCBI · Source |
Database record |
Not applicable | Search returned taxonomy id 28511 (checked 2026-10-25). Methods, limits and fundingRead: full-text | |
| Nam 2020 Pharmacological Effects of Agastache rugosa against Gastritis Using a Network Pharmacology Approach. Biomolecules · PMID 32916904 |
Animal research animal |
Mice with acid-and-alcohol stomach injury; macrophage cells; computer network analysis | Agastache rugosa extract aerial parts Not given here Not given here · vs Not given here |
A. rugosa relieved mucosal damage in the mouse model. Computer analysis linked acacetin and luteolin to inflammation-related genes (AKT1, NFKBIA, MAPK3). Protective in mice; mechanism is a prediction Methods, limits and fundingOutcomes: Stomach lining damage; network targets Limitations: Abstract only. Mouse and computer work, not people. Funding and conflicts: No conflicts declared. Read: abstract |
| Nechita 2023 Agastache Species: A Comprehensive Review on Phytochemical Composition and Therapeutic Properties. Plants (Basel) · PMID 37631149 |
Systematic review in-vitro |
Literature review (PubMed and Scopus, PRISMA-style) of Agastache species | Agastache species, mostly A. rugosa aerial parts and oils Not applicable Not applicable · vs Not applicable |
A. rugosa is native to East Asia while the rest of the genus is North American. Flavonoids, phenolic acids, phenylpropanoids and monoterpenes dominate. Reported effects (antioxidant, cytotoxic, antimicrobial, anti-atherosclerotic, cardioprotective) come from lab and animal work. Chemistry and lab effects, no human trials summarized Methods, limits and fundingOutcomes: Chemistry and reported effects Limitations: Abstract only. The abstract does not describe any human trial. Funding and conflicts: No conflicts declared. Read: abstract |
| PubChem 2026 PubChem records: estragole (CID 8815), tilianin (CID 5321954), rosmarinic acid (CID 5281792), pogostone (CID 54695756) PubChem · Source |
Database record |
Not applicable | CIDs and formulas checked by name lookup 2026-10-25: estragole C10H12O, tilianin C22H22O10, rosmarinic acid C18H16O8, pogostone C12H16O4. Methods, limits and fundingRead: full-text | |
| See PMC record 2022 Changes in human EEG activity in response to Agastache rugosa essential oil exposure. Behavioral Sciences (Basel) · Source |
Non randomized |
38 38 healthy volunteers (19 men, 19 women) |
Agastache rugosa essential oil (inhaled); oil was 89.49% estragole aerial parts (oil) Inhaled diluted oil; trial setting only Single exposure session · vs No-odor exposure (same people) |
Theta power fell during exposure; relative alpha, slow alpha and spectral edge measures rose. The authors link this to feelings of freshness and concentration; no mood, sleep or thinking test was reported. Brain-wave measures changed; no health outcome Methods, limits and fundingOutcomes: 25 EEG indices from 29 scalp electrodes Limitations: Full text opened (PMC). Small single-group design; EEG changes are not a health benefit. Oil composition (estragole 89.49%, limonene 3.40%, menthone 1.80%, pulegone 1.86%) is from one Korean sample. Funding and conflicts: No external funding; no conflicts declared. Read: full-text |
| Trials 2021 Huoxiang Zhengqi for diarrhea-predominant IBS (CHAIRS): study protocol Trials · Source |
Study protocol |
Not applicable | From our earlier summary, not re-opened: the formula has 11 herbs (including licorice, magnolia bark, atractylodes and pinellia) and its huoxiang is listed as Pogostemon cablin; pregnant and nursing women were excluded. Methods, limits and fundingRead: summary-only | |
| Wei 2023 Huo Xiang Zheng Qi Oral Liquid Combined with 5-HT3 Receptor Antagonists and Dexamethasone Can Prevent Chemotherapy-Induced Nausea and Vomiting for Patients Receiving Multiday Cisplatin-Based Regimen: A Multicenter Trial. J Integr Complement Med · PMID 36999940 · DOI |
Controlled trial |
60 Chemotherapy-naive people having multiday cisplatin-based chemotherapy |
Huoxiang Zhengqi (HXZQ), a multi-herb Chinese patent medicine (oral liquid) added to standard anti-nausea drugs multi-herb formula Trial amount not given here One chemotherapy cycle (overall phase about 3 weeks) · vs Placebo added to the same standard drugs |
Complete response in the acute phase was 63.33% vs 33.33% (p = 0.020), and beyond the risk phase 96.67% vs 46.67%. Days with no nausea or vomiting were 18.10 vs 12.13 overall (p = 0.002). Higher complete-response rate when added to standard drugs Methods, limits and fundingOutcomes: Complete response (no vomiting, no rescue medicine) rate; days without nausea or vomiting Limitations: Abstract only. Exploratory, 60 people. Patients who could not use NK1 antagonist drugs. Adverse-event detail and funding not stated in the abstract. Formula, not the single herb. Registration: ChiCTR2000040123 Read: abstract |
| Xiao 2020 Efficacy of Huoxiang Zhengqi dropping pills and Lianhua Qingwen granules in treatment of COVID-19: a randomized controlled trial. Pharmacol Res · PMID 32781283 · DOI |
Controlled trial |
283 Patients with COVID-19 (3 groups) |
Huoxiang Zhengqi dropping pills plus Lianhua Qingwen granules, both with Western medicine multi-herb formulas Trial amounts not given here 14 days · vs Lianhua granules, or Western medicine alone |
No significant difference in symptom improvement among the three groups (P > 0.05). Nausea, vomiting and limb soreness did better in the combination group. Progression to severe disease: 1.6% vs 8.6% vs 11.1%, not statistically different. No significant difference in the main outcome Methods, limits and fundingOutcomes: Improvement rate of clinical symptoms; progression to severe disease Limitations: Abstract only. The combination arm cannot separate the two formulas. Authors' positive conclusion goes beyond the null main result. Funding and conflicts: Drugs were provided by the makers (TASLY, Yiling), who did not take part in design or analysis, per the authors. Read: abstract |
| Xuan 2025 Chinese herbal formula Huoxiang Zhengqi oral liquid for atopic dermatitis: the CHARM randomized controlled trial. Phytomedicine · PMID 40839987 · DOI |
Controlled trial |
218 Adults in China with mild atopic dermatitis or eczema (110 formula, 108 placebo) |
Huoxiang Zhengqi (HXZQ), a multi-herb Chinese patent medicine (oral liquid) multi-herb formula Trial amount not given here 4 weeks (follow-up to week 8) · vs Placebo |
Adjusted EASI change difference at week 4 was -0.44 (95% CI -0.83 to -0.04; p = 0.033). At week 8, 66% of the formula group vs 50.5% of placebo had a 50% or greater EASI reduction (p = 0.022). Small average EASI difference Methods, limits and fundingOutcomes: Change in Eczema Area and Severity Index (EASI) Limitations: Abstract only. Mild disease only; 4-week treatment; a difference of 0.44 points is small. Formula, not the single herb. Funding and conflicts: Product supplied by the maker (Chongqing Taiji) with no role in design or analysis, per the authors. Read: abstract |
| Yu 2019 Systematic review and meta-analysis of Huoxiang Zhengqi Pills combined with Western medicine for acute gastroenteritis (in Chinese). Zhongguo Zhong Yao Za Zhi · PMID 31602833 · DOI |
Meta-analysis |
4153 People with acute gastroenteritis; 44 randomized trials |
Huoxiang Zhengqi Pills (multi-herb formula) plus usual treatment multi-herb formula Not given in abstract Not given in abstract · vs Usual treatment or norfloxacin alone |
The pills plus usual treatment had a better total effective rate than usual treatment alone and relieved fever better. Adverse reactions did not differ statistically. The overall quality of the included studies was generally low. Better effective rate; low-quality studies Methods, limits and fundingOutcomes: Total clinical effective rate; time to symptom relief; adverse reactions Limitations: Abstract only (Chinese-language paper). Authors say the conclusion needs more high-quality research. Other outcomes could not be concluded. Read: abstract |
What we do not know yet
- No trial of Korean mint alone for nausea, IBS or gastroenteritis.
- Formula trials list patchouli as their huoxiang.
- No human safety, liver or interaction studies of Korean mint.
- Revised EMA estragole statement and EFSA opinion not read.
- Yin-deficiency caution not verified.
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".
Other 6
IBS symptom severity score (IBS-SSS)
Lowered in trials
A questionnaire score for pain, bloating, bowel habit and life impact in IBS.
Low certaintyResults and what it means
Why it was measured
Shows how bad IBS symptoms feel.
Statistical vs. clinical meaning
A small average difference; the clinical importance is not stated in the abstract.
Safety implication
None specific.
| Study | Result | People | Product |
|---|---|---|---|
| 9 | Mean difference -10.92 points more than placebo (95% CI -18.93 to -2.90) | 212 adults with IBS-D | Huoxiang Zhengqi oral liquid, 4 weeks |
Complete response (no vomiting, no rescue medicine)
Raised in trials
The share of patients with no vomiting and no rescue drugs in a set time window.
Very low certaintyResults and what it means
Why it was measured
The standard way to judge anti-nausea treatment.
Statistical vs. clinical meaning
Exploratory small trial.
Safety implication
None specific.
| Study | Result | People | Product |
|---|---|---|---|
| 23 | 63.33% vs 33.33% (acute phase); 96.67% vs 46.67% (beyond the risk phase) | 60 patients on multiday cisplatin | Huoxiang Zhengqi oral liquid plus standard drugs |
Total clinical effective rate
Raised in trials
A trial-defined 'improved' rate used in Chinese studies.
Very low certaintyResults and what it means
Why it was measured
Summarises recovery in many trials.
Statistical vs. clinical meaning
Definitions differ between trials and study quality was low.
Safety implication
None specific.
| Study | Result | People | Product |
|---|---|---|---|
| 26 | Higher with the pills plus usual treatment than usual treatment alone (numbers not in the abstract) | 4,153 patients in 44 trials | Huoxiang Zhengqi pills plus usual treatment |
Wrinkle size and transepidermal water loss
Lowered in trials
Skin-imaging measures of wrinkles and water lost through the skin surface.
Very low certaintyResults and what it means
Why it was measured
Used to judge skin aging and barrier strength.
Statistical vs. clinical meaning
Measured by instrument; clinical value unclear.
Safety implication
None noted.
| Study | Result | People | Product |
|---|---|---|---|
| 3 | Both A. rugosa extract and the complex lowered wrinkle size and water loss vs placebo at 8 and 12 weeks | 45 participants | A. rugosa extract or complex tablets, 12 weeks |
Eczema Area and Severity Index (EASI)
Lowered in trials
A clinician score of eczema extent and severity.
Very low certaintyResults and what it means
Why it was measured
Standard eczema outcome.
Statistical vs. clinical meaning
Statistically significant but a small difference.
Safety implication
None noted.
| Study | Result | People | Product |
|---|---|---|---|
| 25 | Adjusted difference -0.44 at week 4 (95% CI -0.83 to -0.04) | 218 adults with mild eczema | Huoxiang Zhengqi oral liquid, 4 weeks |
EEG theta and alpha power
Mixed results in trials
Brain-wave measures taken with scalp electrodes.
Not enough evidenceResults and what it means
Why it was measured
Used to study how scents affect brain activity.
Statistical vs. clinical meaning
A brain-activity marker, not a symptom or benefit.
Safety implication
The oil is rich in estragole.
| Study | Result | People | Product |
|---|---|---|---|
| 21 | Theta power fell and alpha-type measures rose during oil exposure vs no odor | 38 healthy volunteers | Inhaled A. rugosa essential oil |
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
- Estragole: a known liver-cancer concern in animals at high exposure. One study found a Korean mint oil was about 89% estragole, and the EU medicines agency's 2005 list gives A. rugosa oil as about 90%. The EMA herbal committee (HMPC) calls estragole a naturally occurring genotoxic carcinogen (animal data) with a DNA potency like safrole. In its draft 2014 revision it also says short-term adult use of herbal medicines at recommended amounts does not pose a significant cancer risk, because the harmful activation is dose-dependent and much weaker at low exposure, but that exposure should be kept as low as practically achievable. A later revised statement with new guidance values exists; we did not read it. Estragole content varies between plants. Authoritative guidance 4 5 6 21
- Do not swallow the essential oil. The concentrated oil is mostly estragole in the sample studied. Brain-wave studies used it as a diluted scent only. We found no safety study of swallowing it. Authoritative guidance 21 4
- Pregnancy, breastfeeding and young children. The EMA committee says exposure to estragole should be minimised in young children and in pregnant and breastfeeding women. No safety study of Korean mint in these groups was found, and trial protocols excluded pregnant and nursing women. Authoritative guidance 4 5 22
- Which plant is 'huo xiang'?. Huo xiang usually means Agastache rugosa; guang huo xiang means Pogostemon cablin (patchouli). Both are in the mint family and look alike when dried. A 2022 Korean food-safety case found them sold without being told apart. Formula trials list Pogostemon cablin, so their results and safety do not transfer to Korean mint. Case report 12 22 14
- Traditional caution in 'yin deficiency' (NOT verified). Traditional Chinese texts are often described as advising caution with aromatic, drying herbs in people with 'yin deficiency' (dry, hot, depleted patterns). We did not find an authoritative source to confirm the exact wording for huo xiang, so treat this as unconfirmed tradition, not medical advice. Traditional use
Side effects 3
| Effect | How often | Severity and recovery | Evidence |
|---|---|---|---|
| No serious adverse events in the main formula trial Applies to the Huoxiang Zhengqi oral liquid over 4 weeks, not to the single herb. | Not established | not applicable not applicable | Controlled trial 9 |
| No statistical difference in adverse reactions versus usual care Low-quality trials of the formula; details not in the abstract. | Not established | not applicable not applicable | Meta-analysis 26 |
| Adverse events not reported in the abstract The skin-extract and chemotherapy trials do not state adverse events in their abstracts. | Not established | unknown unknown | Controlled trial 3 23 |
Liver
No case of liver injury linked to Agastache rugosa was found, and no LiverTox chapter for it was confirmed. The estragole in the plant is activated in the liver (by CYP1A2 and SULT1A1 enzymes) and causes liver tumours in rodents at high doses. In human liver cells, DNA damage appeared only at high lab concentrations, and one 2026 study found low-level estragole DNA adducts in human liver samples, well below levels that cause mutations in cells. Whether this matters for people using the herb is not established. 1 2 15 5
How often. No frequency can be given.
Monitoring. No agency monitoring advice for the liver was found. Seek care for yellow skin or eyes, dark urine or severe tiredness after using a herbal product.
This is a safety connection. It is not evidence that Korean Mint supports liver health.
Medicines and supplements 3
| With | Why it matters | Importance | Evidence | What to do |
|---|---|---|---|---|
| Medicines cleared by CYP1A2 (for example caffeine-like or some antipsychotic and asthma drugs) prescription | Estragole is activated by CYP1A2 in lab studies. Whether Korean mint changes how drugs are handled by this enzyme in people is unknown. | Unknown. No human interaction study of Agastache rugosa or estragole was found. | Pharmacological theory Not enough evidence 1 | Ask a pharmacist before combining with medicines that have a narrow safety margin. |
| Standard anti-nausea drugs and chemotherapy prescription | In one small trial the formula was added to standard anti-nausea drugs without a reported problem. | Unknown beyond one 60-person trial of a formula. | Controlled trial Very low certainty 23 | Tell your cancer team about any herbal product. |
| Licorice in the Huoxiang Zhengqi formula herb | The formula contains licorice (per the protocol, summary-only); licorice has its own blood-pressure and potassium effects. | Applies to the formula, not to Korean mint. | Authoritative guidance Not enough evidence 22 | Check formula ingredient lists with a pharmacist. |
Who should check first 5
| Situation | Advice | Evidence |
|---|---|---|
| Pregnancy and breastfeeding | Avoid medicinal amounts and the oil. The EMA committee says estragole exposure should be minimised; no Korean mint safety data exist. | Authoritative guidance 4 22 |
| Young children | Avoid the oil; no safety data. The EMA committee says estragole exposure should be minimised in young children. | Authoritative guidance 4 |
| Existing liver disease | Ask a doctor first: estragole is processed in the liver. No human liver-safety data exist. | Pharmacological theory 1 |
| 'Yin deficiency' pattern (traditional caution, NOT verified) | Traditional practitioners may advise caution; we could not confirm this from an authoritative source. | Traditional use |
| Allergy to mint-family plants | Possible cross-reaction is plausible; no case report was found. | Pharmacological theory |
Overdose, product quality and regulators
Summary. The main documented concern is estragole, which causes liver tumours in rodents at high exposure. Human risk from normal food-like or short-term medicinal use is judged low by the EMA's draft statement, but the oil is very concentrated.
Animal. Rodent liver-cancer data underlie the EMA statements (not re-read in detail here).
Human doses studied. Trials used formulas for 2 to 4 weeks, one extract for 12 weeks. These amounts are not recommendations.
High dose or long term signals. Long-term safety of Korean mint in people has not been studied.
Overdose response. Not studied.
Genotoxicity. Estragole is a genotoxic carcinogen in animals per the EMA. In human liver cells a threshold effect was reported, with chromosome damage only at high lab concentrations.
Toxic plant parts. The essential oil is the most estragole-rich part (about 89-90% in samples). A pulegone-rich chemotype also exists; pulegone safety was not researched.
The documented issue is mix-ups between huo xiang plants and variation in oil chemistry. Pesticide, heavy-metal and adulteration surveys for Korean mint were not found.
Mix-up between Agastache rugosa and Pogostemon cablin. A 2022 conference abstract describes a Korean case where A. rugosa was sold as Kwakhyang without telling the two apart; a DNA test was developed. 12
Oil chemistry varies. One sample was 89.49% estragole; a genome paper describes a pulegone- and isomenthone-making chemotype. 21 13
| Body | Action | Date |
|---|---|---|
| European Medicines Agency (HMPC) (European Union) | Public statement on estragole: genotoxic carcinogen in animals; exposure should be minimised in young children and pregnant and breastfeeding women; short-term adult use at recommended amounts not judged a significant cancer risk (draft revision 1, 2014). No EU herbal monograph for Agastache rugosa was found. source | 2005 final and 2014 draft read 2026-10-25 |
When to get medical help
- Yellow skin or eyes, dark urine or severe tiredness after a herbal product: stop it and seek medical care.
- Swelling of the face or throat, trouble breathing or widespread hives: call emergency services.
- Persistent vomiting, bloody stools, high fever or signs of dehydration: seek care; do not rely on herbs.
- If you are pregnant or breastfeeding and swallowed the oil: contact your doctor or poison centre.
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 Korean mint (huo xiang)?
Is huo xiang the same as patchouli?
Does Korean mint help nausea?
It is used for nausea traditionally. In one small trial a multi-herb formula added to standard drugs gave a higher no-vomiting rate in chemotherapy patients, but that trial did not test Korean mint alone.
Does it help irritable bowel syndrome?
What is estragole and why does it matter?
Is it safe in pregnancy or breastfeeding?
Can it harm the liver or interact with medicines?
Is it safe for people with 'yin deficiency'?
Traditional practitioners may advise caution with aromatic, drying herbs in this pattern, but we could not confirm the wording for huo xiang from an authoritative source. Ask a qualified practitioner.
Is Korean mint good for skin?
One small trial by the product makers found smaller wrinkles and less skin water loss with an extract than with placebo. It has not been repeated.
Does the scent affect the brain?
Smelling the diluted oil changed brain-wave measures in 38 adults, but no mood or concentration outcome was tested.
How much should I take?
We do not give amounts. Ask a doctor or pharmacist, especially if you take medicines or are pregnant.
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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 started from our earlier evidence summary for huo xiang, re-checked PubMed records and abstracts, read the EMA estragole statements (2005 final and 2014 draft) and an open-access EEG paper, and checked plant names in GBIF and NCBI Taxonomy and compounds in PubChem. Not read: the revised EMA statement, EFSA opinion, NCCIH, LiverTox, LactMed, WHO and Chinese Pharmacopoeia entries, and the full texts of the formula trials. Certainty ratings are the compiler's reading.
- How we rate evidence
- See "How we rate evidence" in the Evidence tab.
- Independence
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Sources 26
Each source was opened and checked. Where we read only the abstract, it says so. The small numbers in the text point here.
- Ackermann G, Peil M, Quarz C, et al.. Molecular dosimetry of estragole and 1'-hydroxyestragole-induced DNA adduct formation, clastogenicity and cytotoxicity in human liver cell models.. Arch Toxicol. 2025. PMID 40397106. DOI 10.1007/s00204-025-04084-2. (abstract)
- Ackermann G, Abel-Beckmann M, Quarz C, et al.. Formation and persistence of estragole-derived DNA adducts in human liver cells and tissue.. Arch Toxicol. 2026. PMID 41915187. DOI 10.1007/s00204-026-04364-5. (abstract)
- Cho Y, Shen J, Li J, et al.. Comparative Effects of Agastache rugosa Extract and a Complex of Agastache rugosa, Ficus carica, and Lycium barbarum Extracts on Skin Aging: a randomized, double-blind, placebo-controlled trial.. J Med Food. 2026. PMID 41817298. DOI 10.1177/1096620X261431197. (abstract)
- European Medicines Agency (HMPC). Public statement on the use of herbal medicinal products containing estragole (final, 23 November 2005). European Medicines Agency (HMPC). 2005. (full-text)
- European Medicines Agency (HMPC). Public statement on the use of herbal medicinal products containing estragole, DRAFT revision 1 (24 November 2014). European Medicines Agency (HMPC). 2014. (full-text)
- Fimea (Finnish Medicines Agency). Safety limits for medicinal products containing estragole have been revised. Fimea (Finnish Medicines Agency). 2024. (summary-only)
- GBIF. GBIF species match: Agastache rugosa (Fisch. & C.A.Mey.) Kuntze. GBIF. 2026. (full-text)
- GBIF. GBIF species match: Pogostemon cablin (Blanco) Benth.. GBIF. 2026. (full-text)
- Guo X, Cheng T, Xuan M, et al.. Huoxiang Zhengqi oral liquid for irritable bowel syndrome with diarrhea: a multicenter, double-blind, randomized controlled trial.. Phytomedicine. 2025. PMID 41297321. DOI 10.1016/j.phymed.2025.157567. (abstract)
- Jiang GZ, Ma ZY, Hou HD, et al.. Gastrointestinal motility modulation efficacy-related chemical marker findings and QAMS-based quality control of Agastache rugosa.. J Pharm Biomed Anal. 2025. DOI Lab/animal only.. (https://pubmed.ncbi.nlm.nih.gov/39854932/)
- Kim ES, Park BI, Kim YH, et al.. The Inhibitory Effect of Agastache rugosa Essential Oil on the Dental Biofilm.. Molecules. 2024. PMID 39459275. DOI 10.3390/molecules29204907. (abstract)
- Korean Society of Crop Science. DNA-based PCR to distinguish A. rugosa and P. cablin (conference abstract). Korean Society of Crop Science. 2022. (summary-only)
- Liu C, Li D, Dang J, et al.. Haplotype-resolved genome of Agastache rugosa (Huo Xiang) provides insight into monoterpenoid biosynthesis and gene cluster evolution.. Hortic Res. 2025. PMID 40224328. DOI 10.1093/hr/uhaf034. (abstract)
- Mrisho II, Musazade E, Chen H. Unlocking the Therapeutic Potential of Patchouli Leaves: A Comprehensive Review of Phytochemical and Pharmacological Insights.. Plants (Basel). 2025. PMID 40219102. (abstract)
- NCBI. NCBI Bookshelf title search (LiverTox / LactMed) for Agastache, huoxiang, patchouli, estragole. NCBI. 2026. (summary-only)
- NCBI. NCBI Taxonomy: Agastache rugosa. NCBI. 2026. (full-text)
- NCBI. NCBI Taxonomy: Pogostemon cablin. NCBI. 2026. (full-text)
- Nam HH, Kim JS, Lee J, et al.. Pharmacological Effects of Agastache rugosa against Gastritis Using a Network Pharmacology Approach.. Biomolecules. 2020. PMID 32916904. (abstract)
- Nechita MA, Toiu A, Benedec D. Agastache Species: A Comprehensive Review on Phytochemical Composition and Therapeutic Properties.. Plants (Basel). 2023. PMID 37631149. (abstract)
- PubChem. PubChem records: estragole (CID 8815), tilianin (CID 5321954), rosmarinic acid (CID 5281792), pogostone (CID 54695756). PubChem. 2026. (full-text)
- See PMC record. Changes in human EEG activity in response to Agastache rugosa essential oil exposure.. Behavioral Sciences (Basel). 2022. (full-text)
- Trials. Huoxiang Zhengqi for diarrhea-predominant IBS (CHAIRS): study protocol. Trials. 2021. (summary-only)
- Wei H, Sun Y, Xie L, et al.. Huo Xiang Zheng Qi Oral Liquid Combined with 5-HT3 Receptor Antagonists and Dexamethasone Can Prevent Chemotherapy-Induced Nausea and Vomiting for Patients Receiving Multiday Cisplatin-Based Regimen: A Multicenter Trial.. J Integr Complement Med. 2023. PMID 36999940. DOI 10.1089/jicm.2022.0672. (abstract)
- Xiao M, Tian J, Zhou Y, et al.. Efficacy of Huoxiang Zhengqi dropping pills and Lianhua Qingwen granules in treatment of COVID-19: a randomized controlled trial.. Pharmacol Res. 2020. PMID 32781283. DOI 10.1016/j.phrs.2020.105126. (abstract)
- Xuan M, Guo X, Li G, et al.. Chinese herbal formula Huoxiang Zhengqi oral liquid for atopic dermatitis: the CHARM randomized controlled trial.. Phytomedicine. 2025. PMID 40839987. DOI 10.1016/j.phymed.2025.157141. (abstract)
- Yu DD, Liao X, Xie YM, et al.. Systematic review and meta-analysis of Huoxiang Zhengqi Pills combined with Western medicine for acute gastroenteritis (in Chinese).. Zhongguo Zhong Yao Za Zhi. 2019. PMID 31602833. DOI 10.19540/j.cnki.cjcmm.20190513.502. (abstract)