Interactions by Drug Class
Supplement interactions by drug class: blood thinners, antidepressants, transplant, HIV and cancer drugs, statins, diabetes, sedatives, corticosteroids, with documented, reported and preliminary labels and sources.
Content last updated . This page has not been medically reviewed.
Only interactions that a source states are listed. Not on this list does not mean safe. Ask a pharmacist. We do not list doses. Labels are explained in How interactions work. "Documented caution" and "Stated risk" mean the source warns the interaction may happen without giving study detail.
| Drug class | Supplement | What the source says | Label |
|---|---|---|---|
| Blood thinners (warfarin) | Ginkgo | May increase the risk of bleeding with anticoagulants [1] | Documented caution |
| Garlic supplements | May increase bleeding risk; tell providers, especially with anticoagulants or aspirin [2] | Documented caution | |
| Glucosamine | May increase the effects of warfarin, raising the risk of serious bruising and bleeding [3] | Stated risk | |
| Vitamin E, aspirin | Each can thin the blood; together with warfarin may increase risk of internal bleeding or stroke [4] | Documented | |
| Asian ginseng | May interfere with blood clotting [5] | Stated risk | |
| St. John's wort | Decreases warfarin's effect [6] | Documented | |
| Vitamin K foods | See Functional food safety | Documented | |
| Antidepressants and other serotonin drugs | St. John's wort | May increase serotonin-related side effects, which can be serious; also weakens some antidepressants (amitriptyline, bupropion) [7] | Documented |
| Transplant (cyclosporine) | St. John's wort | Weakens cyclosporine [7][6] | Documented |
| HIV medicines (indinavir, nevirapine) | St. John's wort | Decreases effects [6][4] | Documented |
| Heart medicines (digoxin, ivabradine) | St. John's wort | Decreases effects [6] | Documented |
| Cancer medicines (irinotecan, imatinib) | St. John's wort | Decreases effects [6] | Documented |
| Statins (simvastatin) | St. John's wort | Decreases effects [6] | Documented |
| Grapefruit | FDA: affects some statins; see Grapefruit [8] | Documented | |
| Birth control pills | St. John's wort | Less effective [4] | Documented |
| Diabetes (metformin) | Goldenseal | Metformin levels fell about 25% in healthy adults given goldenseal extract; enough to potentially hinder glucose control [6] | Preliminary |
| Beta-blockers (nadolol) | Green tea, high doses | Reduced blood levels in a study [6] | Preliminary |
| Sedatives and anti-anxiety (benzodiazepines) | Ashwagandha | Preliminary evidence it may increase effects of some benzodiazepines and sedatives [3] | Preliminary |
| Kava | Should not be used with sedatives, benzodiazepines or alcohol [9] | Documented caution | |
| Corticosteroids | Licorice | Interactions have been reported [10] | Reported |
| Antihistamine (fexofenadine) | Black cohosh, St. John's wort | May interfere with effectiveness [11] | Stated risk |
| Many medicines | Goldenseal, kratom, CBD | May interact with many medications, including over-the-counter ones [11] | Stated risk |
Classes where we found no sourced interaction list
Thyroid medicines, anticonvulsants (other than as narrow-range examples) and kidney medicines: proper evidence was not found in the sources we could read. NIH's Office of Dietary Supplements was blocked from our system. [12]
References
- National Center for Complementary and Integrative Health (NIH). Ginkgo: Usefulness and Safety. Read 2026-10-22.
- National Center for Complementary and Integrative Health (NIH). Garlic: Usefulness and Safety. Read 2026-10-22.
- National Center for Complementary and Integrative Health (NIH). Know the Science: Some Supplements May Increase the Effects and Side Effects of Medications. Read 2026-10-22.
- U.S. Food and Drug Administration. Mixing Medications and Dietary Supplements Can Endanger Your Health. Read 2026-10-22.
- National Center for Complementary and Integrative Health (NIH). Asian Ginseng: Usefulness and Safety. Read 2026-10-22.
- National Center for Complementary and Integrative Health (NIH). Know the Science: Some Supplements May Decrease the Effects of Medications. Read 2026-10-22.
- National Center for Complementary and Integrative Health (NIH). St. John's Wort: Usefulness and Safety. Read 2026-10-22.
- U.S. Food and Drug Administration. Grapefruit Juice and Some Drugs Don't Mix. Summarized from a search result; check the page for the current text.
- National Center for Complementary and Integrative Health (NIH). Kava: Usefulness and Safety. Read 2026-10-22.
- National Center for Complementary and Integrative Health (NIH). Licorice Root: Usefulness and Safety. Read 2026-10-22.
- National Center for Complementary and Integrative Health (NIH). Know the Science: Interactions With Over-the-Counter Medications. Read 2026-10-22.
- Office of Dietary Supplements (NIH). Fact sheets. Access was blocked (HTTP 403) from our system on 2026-10-22; we did not read it and cite nothing from it.
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.