Drug Database - St. John's Wort

Common Names: St. John's wort, hypericum, Klamath weed, goat weed

Latin Name: Hypericum perforatum

Classification: Herb / Dietary Supplement

St. John's wort has been used for centuries to treat mental disorders and nerve pain. St. John's wort has also been used as a sedative and a treatment for malaria, as well as a balm for wounds, burns, and insect bites. Today, St. John's wort is used by some for depression, anxiety, and/or sleep disorders.

There is some scientific evidence that St. John's wort is useful for treating mild to moderate depression. However, two large studies, one sponsored by National Center for Complementary and Alternative Medicine (NCCAM), showed that the herb was no more effective than placebo in treating major depression of moderate severity.

NCCAM is studying the use of St. John's wort in a wider spectrum of mood disorders, including minor depression.

St. John's wort may cause increased sensitivity to sunlight. Other side effects can include:

• anxiety
• dry mouth
• dizziness
• gastrointestinal symptoms
• fatigue
• headache
• sexual dysfunction

Research shows that St. John's wort interacts with some drugs. The herb affects the way the body processes or breaks down many drugs; in some cases, it may speed or slow a drug's breakdown. Drugs that can be affected include:

• Antidepressants
• Birth control pills
• Cyclosporine, which prevents the body from rejecting transplanted organs
• Digoxin, which strengthens heart muscle contractions
• Indinavir and possibly other drugs used to control HIV infection
• Irinotecan and possibly other drugs used to treat cancer
• Warfarin and related anticoagulants

When combined with certain antidepressants, St. John's wort may increase side effects such as nausea, anxiety, headache, and confusion.

St. John's wort is not a proven therapy for depression. If depression is not adequately treated, it can become severe. Anyone who may have depression should see a health care provider. There are effective proven therapies available.

Tell your health care providers about any complementary and alternative practices you use. Give them a full picture of what you do to manage your health. This will help ensure coordinated and safe care.