Interaction: St Johns Wort × Oral Contraceptives
St Johns Wort × Oral Contraceptives
Severity: MODERATE Evidence: well-established
Mechanism
St. John's wort induces CYP3A4, increasing metabolism of estrogen in oral contraceptives.
Effect
Reduced contraceptive efficacy; breakthrough bleeding; unintended pregnancy risk
Management
Avoid combination. Use alternative contraception or avoid St. John's wort.
Source
Hall SD et al. Clin Pharmacol Ther 2003; Murphy PA et al. J Clin Pharmacol 2005
⚠️ MODERATE INTERACTION: Monitor closely if this combination is used.
Disclaimer
This interaction record is for informational purposes only and does not constitute medical advice. Always consult a healthcare provider before starting or stopping any supplement or medication.