Health information to help you understand symptoms. It isn't a diagnosis.
Check symptoms

St. John's wort

Brand names: Herbal supplement

St. John's wort is an herbal supplement sometimes used for mild depression. It interacts with many prescription medicines.

Brand namesHerbal supplement
Type of medicineHerbal supplement
Prescription?Over the counter (herbal supplement)
ImportantThis page is general information, not a prescription. Don't start, stop, or change a medicine without talking to your provider or pharmacist.

Overview

It can make birth control, blood thinners, HIV medicines, and transplant medicines stop working.

What it's used for

  • Mild depression (mixed evidence)

How to take it

  • Talk with your provider or pharmacist before taking it.

Your dose depends on your health and other medicines. Always follow your prescription label, and ask your pharmacist if anything is unclear.

Side effects

Common side effects

  • Sun sensitivity
  • Upset stomach
  • Trouble sleeping
Call 911Agitation, fever, sweating, muscle twitching or stiffness, fast heartbeat, and confusion (possible serotonin syndrome)
Call 911Thoughts of suicide or harming yourself. Call or text 988 any time.

Warnings

  • Supplements aren't tightly regulated; strength varies.

Other medicines, foods, and alcohol

  • It makes birth control, warfarin, apixaban, many HIV and transplant medicines, and others less effective.
  • Antidepressants and triptans add serotonin syndrome risk.

Tell your provider and pharmacist about every medicine, vitamin, and supplement you take.

Pregnancy and breastfeeding

Not recommended in pregnancy.

Missed doses, overdose, and storage

If you miss a dose

Take it as soon as you remember, unless it's almost time for your next dose. Then skip the missed dose. Don't take two doses at once.

If someone takes too much

Call Poison Control at 1-800-222-1222 or get help online at poison.org. Call 911 if the person collapses, has a seizure, has trouble breathing, or can't be woken.

Storing it

Store at room temperature, away from heat and moisture (not in the bathroom), and out of reach of children and pets.

Sources

Last updated 2026-11-13.