St. John’s Wort
Hypericum perforatum
St. John’s Wort is an herb in the Hypericaceae family.
Last reviewed August 3, 2026
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Is St. John’s Wort safe to use?
Significant interaction risk: induces liver enzymes (CYP3A4) that speed up metabolism of many medications, including hormonal birth control (can reduce effectiveness), blood thinners like warfarin, immunosuppressants (organ transplant rejection has occurred), and some HIV and cancer medications. Combined with SSRIs, SNRIs, or MAOIs, it carries a risk of serotonin syndrome, a potentially life-threatening reaction. Do not combine with any prescription medication without a pharmacist or physician's review. Also increases sun sensitivity.
This is educational information, not medical advice. See our full Disclaimer before use.
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