Feel-good kava has a down side

Kava, an herb from the South Pacific islands, has long been used to create a sense of relaxation and well-being. But cases of adverse side effects associated with the use of kava supplements are mounting.

Uses: The root from the kava plant historically has been used as a social drug. As a supplement, it’s touted as a mild natural tranquilizer that can relieve anxiety and stress. It’s sometimes used to treat insomnia.

Dose: Usually 300 milligrams per day.

Precautions: Last month, the Centers for Disease Control and Prevention issued a report on two cases of liver failure in the U.S. linked to kava supplements, including one in a 14-year-old girl who needed a liver transplant. The herb can be toxic to the liver, especially among people with liver disease or who take drugs that affect the liver. Kava in very high doses can cause mental impairment. It should not be combined with alcohol or sedating drugs because the herb can intensify the effect. Some people are allergic to kava.


Research: Even with its potential risks, interest in kava as a medicine remains high. Researchers are exploring whether low doses could be an acceptable replacement for prescription drugs for the short-term treatment of anxiety and stress-related insomnia.

Dietary supplement makers are not required by the U.S. government to demonstrate that their products are safe or effective. Ask your health-care provider for advice on selecting a brand.