Guidance only, based on EMA HMPC monographs, NCCIH/NIH, BOT-PLUS and the Summary of Product Characteristics.
It does NOT replace the judgement of a pharmacist or a medical consultation. Always tell your prescriber and pharmacist about any supplement you take. Brand availability and licensing differ between countries.
Look up a supplement
By common name, Latin name or brand. If it is not in the curated dataset, the AI writes the record from official sources.
Quick picks:
Curated catalogue
28 records covering herbal medicines, vitamins and minerals with their most relevant drug interactions. Click to open.
The four that catch people out
- St John's wort. The single most consequential herbal interaction. It induces CYP3A4 and P-glycoprotein, so it can cause contraceptive failure and can push a transplant recipient into rejection. People buy it over the counter for low mood and do not think of it as medication.
- Liquorice. Not just a sweet: glycyrrhizin causes pseudohyperaldosteronism, so it raises blood pressure, lowers potassium and makes digoxin more toxic. It turns up in herbal teas and cough remedies.
- Ginkgo. Adds to the bleeding risk of anticoagulants, antiplatelets and NSAIDs. It should be stopped 5-7 days before surgery.
- Vitamin K. A direct antagonist of warfarin and acenocoumarol. The problem is rarely the diet itself but a sudden change in it — including starting a K2 supplement.
The pattern behind all four is the same: these are products people buy for themselves, so they never reach the medication list unless someone asks. Ask.
Frequently asked questions
Can natural supplements interact with prescription medicines?
Yes, and often in a clinically important way. St John's wort is a powerful enzyme inducer that can make contraceptives, anticoagulants, antiretrovirals or ciclosporin less effective. Liquorice can raise blood pressure and increase digoxin toxicity. Ginkgo increases bleeding risk with anticoagulants and NSAIDs.
What should I do if I take a supplement and I am prescribed a new medicine?
Tell the prescriber and the pharmacist every time. Take the pack with you so the full composition can be checked. Many people do not think of supplements as medication and leave them out of their medical history.
Which sources do you use?
EMA HMPC monographs, NCCIH/NIH, the Memorial Sloan Kettering herbal database, the Natural Medicines database and e-lactancia, plus BOT-PLUS and the Spanish Summary of Product Characteristics. When a supplement is not in the curated dataset, the AI writes the record from those same sources.
Are supplements safe in pregnancy?
Only the ones specifically recommended: folic acid before conception, iodine, vitamin D if deficient, and DHA. Most herbal products are advised against or contraindicated because the data are insufficient. Always check with your midwife or doctor.