Herb–Drug Interaction Checker
Type any botanical supplement or prescription medication worldwide.
Cross-referencing global biomedical databases...
Disclaimer: Powered by iNaturalist Botanical Index, U.S. National Library of Medicine (RxNorm), and Clinical Research Archives. Educational use only. Always consult a licensed physician before altering supplement or medication intake.
Herbal safety reference
Herb Drug Interaction Checker
Enter what you take. Every result is graded twice — how serious the interaction could be, and how strong the evidence for it actually is.
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This tool does not tell you anything is safe. It reports interactions documented in the medical literature, and it checks each one against the official FDA drug label and PubMed while you read — so you can follow the sources yourself rather than take this page's word for it. A blank result means nothing was found; most herb–drug combinations have simply never been studied. These records have not been individually signed off by a clinician. Never start, stop or change a prescribed medicine based on what you read here — take the printout to your pharmacist or prescriber instead.
Findings
Nothing checked yetAdd at least one herb and one medicine.
How to read a result
Each finding carries two independent grades. A combination can be theoretically dangerous but barely studied, or well studied and only mildly relevant — collapsing those into one label is how most interaction checkers mislead people.
| Avoid | Do not combine. Documented harm, or a plausible mechanism with severe consequences. |
| Serious | Do not start without your prescriber's agreement. |
| Monitor | May be workable with monitoring, dose adjustment or spacing of doses. |
| Theoretical | Mechanism or scattered reports only. Worth mentioning, not worth panic. |
| No record | Not in this database. Not the same as safe. |
| Evidence A | Human clinical or pharmacokinetic studies. |
| Evidence B | Published case reports or limited human data. |
| Evidence C | Laboratory or animal work only — mechanism, not outcome. |
| Evidence D | Expert opinion or long-standing traditional caution. |
Why timing matters: enzyme-inducing herbs such as St John's wort keep affecting drug levels for one to two weeks after the last dose. Stopping the herb abruptly can push a drug level up as fast as starting it pushed it down.