st johns wort at a glance
Type
Traditional herbal medicinal product
Licensed role
Relief of slightly low mood and mild anxiety, based on traditional use only
Key safety point
Check all medicines and hormonal contraception for interactions
What is st johns wort used for?
Selected UK products are traditional herbal registrations, not treatments for diagnosed depressive illness.
Traditional relief of slightly low mood.
Traditional relief of mild anxiety.
Seek medical assessment for symptoms suggesting depression.
How does st johns wort work?
Its mood-related action is not fully established. Hyperforin may affect neurotransmitter signalling, including serotonin, and can increase CYP enzymes and P-glycoprotein activity. This can speed removal of other medicines and reduce their effectiveness.
How to take st johns wort
Take by mouth. Swallow film-coated tablets whole with a little liquid; do not chew. Avoid excessive sunbathing, sunbeds and other strong ultraviolet exposure because photosensitivity can occur.
Check with a pharmacist or prescriber before starting if you use any other medicine, including hormonal contraception.
Tell healthcare professionals before an operation or procedure.
st johns wort side effects
Common or expected effects
- Reported effects, with frequency unknown, include indigestion, reduced appetite, nausea, diarrhoea or constipation.
- Rash, hives, itching, tiredness, restlessness, headache, anxiety and dizziness have been reported.
Get urgent medical advice
- Marked sunburn-like reactions after strong sunlight or ultraviolet exposure need medical assessment.
- New mania, severe agitation or major changes in mood or behaviour need prompt assessment.
- Symptoms suggesting serotonin syndrome need urgent medical help.
st johns wort in pregnancy
The selected product is not recommended during pregnancy because adequate safety data are unavailable. Speak to a doctor, midwife or pharmacist rather than self-treating low mood during pregnancy.
st johns wort while breastfeeding
Use while breastfeeding is not recommended because safety has not been established. Discuss low mood and treatment options with a doctor, health visitor or pharmacist.
st johns wort interactions
St John’s wort has many clinically important interactions. A pharmacist or prescriber should review all medicines before it is started or stopped.
Hormonal contraception, including emergency contraception
It can reduce hormone exposure, causing breakthrough bleeding and contraceptive failure; concurrent use should be avoided.
Antidepressants, other serotonergic medicines and triptans
Combining them may increase serotonergic effects and the risk of serotonin syndrome.
Common questions about st johns wort
Answers are fully visible for fast scanning and source review.
Is St John’s wort licensed to treat depression in the UK?
Selected products are traditionally registered for slightly low mood and mild anxiety, based on traditional use only. They are not presented as treatments for diagnosed depression.
Does St John’s wort affect contraception?
Yes. It can reduce the effectiveness of hormonal contraception and increase the risk of breakthrough bleeding and unintended pregnancy.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.