VITAMINS & SUPPLEMENTS · GUIDE
Herbal Nootropics Safety: Liver, Bleeding and Interactions
A plain safety guide to herbs sold for memory and focus: what is known about liver injury, bleeding, seizures, medicine interactions, pregnancy and surgery for ginkgo, bacopa, ashwagandha and others.
Content last updated . This page has not been medically reviewed.
Back to NootropicsQuick answer
"Natural" does not mean safe. Herbs sold for memory and focus act on the body, can interact with medicines, and vary in quality from product to product. The risks differ herb by herb: ginkgo has a bleeding question, ashwagandha has a liver question, and several have limited information for pregnancy. Lack of reports is not proof of safety. Talk to a clinician or pharmacist before using any of them, especially if you take medicines, are pregnant, have liver or kidney disease, or have surgery planned.
Urgent. Yellow skin or eyes, dark urine, severe stomach pain, unusual bleeding, black stools, a seizure or sudden confusion needs urgent medical care. In the US call 911. For a suspected poisoning or overdose call Poison Help 1-800-222-1222; see poisoning: what to do first.
Herb-by-herb safety table
"Unknown" below means not described in the sources we read, which is not the same as safe.| Herb | Liver | Bleeding | Other points from the sources |
|---|---|---|---|
| Ginkgo (leaf extract) | LiverTox: not implicated in liver injury [1] | NCCIH: may raise bleeding risk with anticoagulants such as warfarin; a 2011 meta-analysis of 18 trials did not find a higher bleeding risk on lab clotting measures [2][3] | May be unsafe in pregnancy; can increase seizure risk; fresh seeds are toxic [2][4] |
| Bacopa | LiverTox: not linked to liver enzyme rises or clinically apparent liver injury [5] | Unknown | Interactions and side effects: see the bacopa guide |
| Ashwagandha | Documented concern: rare liver injury cases [6][7] | Unknown | Avoid in pregnancy; not recommended before surgery; may interact with several medicine types [6] |
| Rhodiola | Unknown | Unknown | Losartan interaction reported; little known in pregnancy [8] |
| Lion's mane | LiverTox: not linked to clinically apparent liver injury [9] | Unknown | Stomach discomfort, nausea and rash reported in a clinical study [10] |
Liver
Herbal and dietary supplements are increasingly implicated in drug-induced liver injury worldwide, including ashwagandha in the United States. [11] A case series from India described cholestatic hepatitis from single-ingredient ashwagandha products, and the authors describe acute-on-chronic liver failure with high mortality in people with pre-existing liver disease. [12] If you have liver disease, ask a clinician before any herb; see liver safety and supplements.Bleeding and surgery
Ginkgo has the best-known bleeding question. NCCIH says it may raise bleeding risk in people taking anticoagulants such as warfarin. [2] Memorial Sloan Kettering notes human studies and case reports that it may prolong bleeding time. [4] NCCIH advises that before surgery, some supplements may increase bleeding risk or affect anesthesia, and you should tell your health care providers well ahead. [13] See supplements before surgery.Medicine interactions
Herbs can change how medicines work. Examples in the sources: ginkgo with warfarin, insulin and seizure-threshold medicines [4]; ashwagandha with diabetes, blood pressure, sedative, anti-seizure, immune and thyroid medicines [6]; rhodiola with losartan. [8] Never stop or change a prescribed medicine on your own. Bring a full list to your pharmacist; see medication interactions.Pregnancy, breastfeeding and children
Many supplements have not been tested in pregnant women, nursing mothers or children. [13] Ginkgo may be unsafe in pregnancy and ashwagandha should be avoided. [2][6] See pregnancy and breastfeeding.Older adults, kidney conditions and product quality
Older adults often take several medicines, which raises interaction questions. Kidney-specific data for these herbs were not described in the sources we read, so ask a clinician. Label and quality: what is on the label may not be what is in the product, and "standardized" does not guarantee quality. [13] See quality testing and certifications and nootropic safety and claim checks.Frequently asked questions
Can herbal brain supplements harm the liver?
Some can. Ashwagandha has been linked to liver injury cases, while bacopa and lion's mane were not linked to clinically apparent liver injury in the LiverTox reviews. [7][5][9]
Does ginkgo cause bleeding?
NCCIH says it may increase bleeding risk with anticoagulants, while a meta-analysis of lab clotting measures did not show higher risk. Ask a clinician if you take blood thinners. [2][3]
Should I stop herbs before surgery?
Tell your surgical team about every supplement well in advance and follow their instructions. NCCIH notes some supplements can raise bleeding risk or affect anesthesia. [13]
Are herbal supplements safe in pregnancy?
Often not enough is known. Ginkgo may be unsafe and ashwagandha should be avoided; ask a clinician. [2][6]
Do "natural" herbs interact with medicines?
Yes, some do. Ask a pharmacist to check your full list. [13]
References
- Ginkgo (LiverTox, NIDDK; PubMed record of the book entry). Read 2026-10-22.
- Ginkgo: Usefulness and Safety (NCCIH). Read 2026-10-22.
- Bleeding risk with standardized Ginkgo biloba extract: systematic review and meta-analysis (Pharmacotherapy, 2011). Read 2026-10-22.
- Ginkgo (Memorial Sloan Kettering Cancer Center, About Herbs). Read 2026-10-22.
- Bacopa (LiverTox, NIDDK; PubMed record of the book entry). Read 2026-10-22.
- Ashwagandha: Usefulness and Safety (NCCIH). Read 2026-10-22.
- Ashwagandha (LiverTox, NIDDK; PubMed record of the book entry). Read 2026-10-22.
- Rhodiola: Usefulness and Safety (NCCIH). Read 2026-10-22.
- Lion's Mane (LiverTox, NIDDK; PubMed record of the book entry). Read 2026-10-22.
- Lion's Mane Mushroom (Memorial Sloan Kettering Cancer Center, About Herbs). Read 2026-10-22.
- The contemporary epidemiology, causes, and management of drug-induced liver injury (Hepatology Communications, 2026). Read 2026-10-22.
- Ashwagandha-induced liver injury: a case series from India and literature review (Hepatology Communications, 2023). Read 2026-10-22.
- Using Dietary Supplements Wisely (NCCIH). Read 2026-10-22.
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.