St. John's Wort
St. John's Wort (Hypericum perforatum) is an herbal supplement traditionally used for mild depression. It is a potent inducer of CYP3A4 and CYP2C9 enzymes, which can significantly reduce the effectiveness of many medications.
schedule 3 min read
update
Updated March 1, 2026
Gene Interactions
Safety Notes
Contraindications
concurrent use with SSRIs, SNRIs, or MAOIs
oral contraceptives
immunosuppressants (e.g., cyclosporine)
anticoagulants (e.g., warfarin)
HIV protease inhibitors
Drug Interactions
CYP3A4-substrate drugs
CYP2C9-substrate drugs
serotonergic medications
Content coming soon.