St. John’s Wort: Drug-Supplement Interactions

Last Updated February 2021 | This article was created by familydoctor.org editorial staff and reviewed by Robert "Chuck" Rich, Jr., MD, FAAFP

St. John’s Wort is a plant. It is used in teas, creams and ointments, and dietary supplements. These supplements come in the form of tablets, capsules, and liquid extracts. The supplements are used for a variety of health conditions. These include kidney and lung problems, sleep issues, menopause, attention-deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder, wound care, and depression. Its most common use is for depression. St. John’s Wort does not require a prescription.

Path to improved well being

Dietary supplements can affect how your body processes prescription and over-the-counter medicine. There has been extensive research done on its success. There are mixed reviews. However, we do know that it negatively interacts with a long list of medicines. It can be dangerous. In some cases, it can be deadly. Talk to your doctor before taking St. John’s wort.

Things to consider

St. John’s wort reacts with many different types of medicines. These medicines include:

  • Birth control pills
  • Cyclosporine (medicine used in organ transplants)
  • Digoxin (heart medicine)
  • Some HIV medicines (including indinavir)
  • Some cancer medicines (including irinotecan)
  • Warfarin (blood thinner)
  • Any medicines that affect serotonin (Serotonin is produced by your nerve cells. This can lead to serotonin-related side effects.)

St. John’s Wort causes multiple side effects including:

  • Light sensitivity
  • Anxiety
  • Dry mouth
  • Dizziness
  • Stomach upset
  • Fatigue
  • Headache
  • Sexual dysfunction

Questions to ask your doctor

  • Do all supplements interact with prescription medications?
  • Do any supplements interact with over-the-counter medicines?
  • Do doctors approve of St. John’s Wort?
  • Is it safe to take during pregnancy?