St John’s wort herb extract is a herbal product used for mild nervous tension, low mood or minor sleep disturbance, depending on the extract. It may influence neurotransmitters involved in mood, but it is not suitable for severe depression, suicidal thoughts or intense anxiety without medical assessment.
It is taken by mouth according to the leaflet. The effect is not immediate and may require several weeks. It must not be combined with antidepressants, triptans, some opioids or other serotonergic products without medical advice. St John’s wort can reduce the effectiveness of many medicines, including hormonal contraceptives, anticoagulants, antiepileptics, antivirals, immunosuppressants and some cancer treatments.
Side effects may include nausea, dry mouth, tiredness, restlessness, headache, dizziness, skin reactions and increased sensitivity to sunlight. Avoid intense sun exposure or tanning beds if skin reactions occur. Because interactions are important, patients should tell the doctor and pharmacist about any St John’s wort product.
Seek urgent medical help if severe agitation, confusion, fever, sweating, tremor, intense diarrhoea, severe rash or thoughts of self-harm occur. Before surgery, follow medical advice. During pregnancy, breastfeeding, bipolar disorder or important chronic treatments, St John’s wort should be avoided or used only with medical approval.