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Can I take St John's wort with birth control pills?

Not without a backup method. This one is on the drug's label: pill labels name St John's wort as an herbal product that can make the pill less effective, and advise backup birth control while you take it and for 28 days after. Studies in women on the pill found it sped up the breakdown of the pill's hormones and caused bleeding between periods, and one found signs of ovulation. Talk to your prescriber or pharmacist.

How well documented: On the drug’s label. The medicine’s FDA-approved label names this supplement, or the kind of product it is.

Last reviewed

How we grade evidenceEditorial policy

What's known

  • On the label. Pill labels say herbal products that speed up the CYP3A4 enzyme, including products containing St John's wort, may make the pill less effective or cause bleeding between periods. They tell prescribers to advise a backup method while it is used and for 28 days after stopping it. (Yaz label)
  • Drug-level studies. In 12 women on a combined pill, 900 mg a day of St John's wort for 2 cycles sped up the clearance of the progestin and nearly halved the half-life of the estrogen (23.4 to 12.2 hours). Bleeding between periods rose from 2 of 12 women to 7 of 12. In 18 women on a low-dose pill, bleeding between periods rose from 35% to 77 to 88%, and progestin levels fell about 42 to 44%. (Hall 2003; Pfrunder 2003)
  • Signs the pill may fail. In 16 women on a low-dose pill, St John's wort lowered hormone exposure by 13 to 15% and was followed by follicle growth and probable ovulation, the event the pill is meant to block. Unplanned pregnancies have been reported in women taking both. (Murphy 2005; Pfrunder 2003)
  • How strong the evidence is. A 2016 review by CDC researchers found 4 studies: 3 showed more bleeding between periods, 3 showed lower hormone levels, and one showed probable ovulation. The study with no change used a product low in the plant's active compounds; one low-hyperforin extract did not change pill hormone levels in 16 women. (Berry-Bibee 2016; Will-Shahab 2009)

What to do

  • Talk to your prescriber or pharmacist before you take St John's wort with the pill. Other hormonal methods may be affected too, so ask about yours.
  • If you take both, the label's advice is a backup method of birth control, such as condoms, the whole time and for 28 days after your last dose of St John's wort. (Yaz label)
  • New bleeding between periods while taking both is a sign to call your prescriber.
  • If you might be pregnant, are planning a pregnancy or are breastfeeding, ask your doctor or midwife: NCCIH says St John's wort may be unsafe in pregnancy. (NCCIH)
  • Don't stop or change a prescribed medicine on your own.

Sources

  1. US National Library of Medicine. Yaz (drospirenone and ethinyl estradiol) tablets: prescribing information. DailyMed, revised May 2025. DailyMed
  2. National Center for Complementary and Integrative Health. St. John's Wort. Last updated May 2025. NCCIH
  3. Hall SD, et al. The interaction between St John's wort and an oral contraceptive. Clin Pharmacol Ther. 2003. PubMed 14663455 · doi:10.1016/j.clpt.2003.08.009
  4. Pfrunder A, et al. Interaction of St John's wort with low-dose oral contraceptive therapy: a randomized controlled trial. Br J Clin Pharmacol. 2003. PubMed 14616430 · doi:10.1046/j.1365-2125.2003.02005.x
  5. Murphy PA, et al. Interaction of St. John's Wort with oral contraceptives: effects on the pharmacokinetics of norethindrone and ethinyl estradiol, ovarian activity and breakthrough bleeding. Contraception. 2005. PubMed 15914127 · doi:10.1016/j.contraception.2004.11.004
  6. Berry-Bibee EN, et al. Co-administration of St. John's wort and hormonal contraceptives: a systematic review. Contraception. 2016. PubMed 27444983 · doi:10.1016/j.contraception.2016.07.010
  7. Will-Shahab L, et al. St John's wort extract (Ze 117) does not alter the pharmacokinetics of a low-dose oral contraceptive. Eur J Clin Pharmacol. 2009. PubMed 19015839 · doi:10.1007/s00228-008-0587-2