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Can I take St John's wort and Contraceptive pill together?

Drug interaction guide

Taking St John's Wort can make your contraceptive pill much less effective. This significantly increases the risk of an unplanned pregnancy. You may also experience 'breakthrough bleeding' or spotting between periods.

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Why this happens

St John's Wort is a 'liver enzyme inducer'. This means it speeds up the process by which your liver breaks down the hormones (oestrogen and progestogen) found in the contraceptive pill. Because the hormones are cleared from your body much faster than normal, their levels drop too low to reliably prevent pregnancy.

You should not take St John's Wort if you are using any form of hormonal contraception (including the combined pill, the mini-pill, implants, or patches). If you have already started taking it, continue using your pill but use an extra barrier method of contraception (like condoms) immediately. Speak to your GP or pharmacist about alternative treatments for your mood that do not interfere with your birth control.

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Contraceptive failure

St John's wort significantly reduces the effectiveness of the contraceptive pill. This can lead to unplanned pregnancy. You must use an additional barrier method of contraception (such as condoms) or switch to a non-hormonal contraceptive method while taking St John's wort and for four weeks after stopping it.

Depression and Mental Health

Like other antidepressants, St John's wort may increase the risk of suicidal thoughts or self-harm, particularly when first starting treatment. Seek immediate medical help if your mood worsens.

Drug Interactions

St John's wort significantly reduces the effectiveness of many essential medicines, including the contraceptive pill, blood thinners (warfarin), epilepsy medications, and organ transplant drugs. Do not start it without a pharmacist checking your current medications.

Serotonin Syndrome

Taking St John's wort with other antidepressants or triptans (for migraine) can cause serotonin syndrome, a potentially life-threatening condition involving high fever, agitation, and muscle rigidity.

Photosensitivity

St John's wort can make your skin significantly more sensitive to sunlight, leading to severe sunburn or skin reactions even with limited exposure.

Alcohol

It is best to avoid or strictly limit alcohol while taking St John's Wort. Combining the two can increase drowsiness and dizziness, and may worsen the side effects of the herbal remedy.

It is best to avoid or strictly limit alcohol while taking the pill. While alcohol does not directly stop the pill from working, being intoxicated increases the risk of forgetting to take your pill or vomiting shortly after taking it, which renders the contraception ineffective.

Foods high in Tyramine (e.g., aged cheeses, cured meats, soy sauce, marmite, overripe fruit)

While less common than with older prescription antidepressants, St John's Wort can potentially interact with tyramine-rich foods, leading to a sudden, dangerous increase in blood pressure (hypertensive crisis). You should consume these foods in moderation.

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Taking multiple medicines? Our Medicines Interaction Checker helps you check whether your prescriptions, over-the-counter medicines, and supplements are safe to take together. Simply search for your medicines to see potential interactions and what to do about them.

Disclaimer

This information is for general educational purposes only and should not be relied upon as a substitute for professional medical advice. Always consult your GP, pharmacist, or another qualified healthcare professional before making decisions about your medications. Individual circumstances may vary, and only a healthcare professional who knows your medical history can provide personalised guidance.

Article history

The information on this page is written and peer reviewed by qualified clinicians.

  • 25 Jan 2026 | Originally published
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