Kava

Background

• Kava is native to the South Pacific and is a member of the pepper family.
• Pacific Islanders have used kava beverages for thousands of years for ceremonial and medicinal purposes. More recently, the use of kava as a beverage has grown both in the Pacific Islands and in other parts of the world. Kava drinks are now sold at kava bars at many locations in the United States. 
• Kava products are sold in the United States as dietary supplements and in some other countries as drugs or herbal medicines. These products are promoted for anxiety and other health conditions.

How Much Do We Know?

• There has been a fair amount of research in people on the use of kava for anxiety, but few studies have been done on other conditions.
• There has also been substantial investigation of rare but sometimes severe cases of liver injury associated with the use of kava.

What Have We Learned?

• Kava supplements may be helpful for anxiety, but they may need to be taken for several weeks to produce an effect. Kava does not appear to be helpful for symptoms of generalized anxiety disorder.
• There isn’t enough evidence to show whether kava is helpful for any other conditions.

What Do We Know About Safety?

• Various kava products have been linked to rare cases of liver injury, some of which have been serious or even fatal. The first reported cases involved medicinal or dietary supplement products that had been extracted with alcohol or acetone, but other cases have involved kava beverages prepared with water. It has been suggested that the use of undesirable varieties (cultivars) of kava plants or inappropriate parts of the plant may be responsible for liver toxicity; other possibilities include the consumption of kava together with alcohol and the adulteration or contamination of kava products. It has also been suggested that genetic differences among people might influence their susceptibility to liver toxicity and that consumption of kava in large amounts or for prolonged periods of time may increase risk.
• Kava can cause digestive upset, headache, dizziness, and other side effects. Long-term use of high doses of kava may cause kava dermopathy, a condition that involves dry, scaly, flaky skin with reddened eyes and temporary yellow discoloration of the skin, hair, and nails.
• Kava should not be used together with other substances that have sedative effects, such as benzodiazepines or alcohol. If you take any type of medicine, talk with your health care provider before using kava or other herbal products; some herbs and medicines interact in harmful ways.
• Kava may have special risks if taken during pregnancy or while breastfeeding because of the presence of harmful pyrone constituents.

Keep in Mind

• Take charge of your health—talk with your health care providers about any complementary health approaches you use. Together, you can make shared, well-informed decisions.
• Federal Regulation of Herbal Products
  • Depending on what’s in them, how they’re intended to be used, and how they’re administered (orally or topically), herbal products are regulated in a variety of ways. Many herbal products intended for oral use are marketed as dietary supplements. The regulatory paths for making and distributing dietary supplements are different than those for drugs. 
  • Unlike drugs, dietary supplements are not approved by the U.S. Food and Drug Administration (FDA) before they are sold to the public. When public health concerns arise about the safety of a dietary supplement or an ingredient including an herb, the FDA can take action to protect the public. Manufacturers and distributors of supplements are responsible for evaluating the safety and labeling of their products before marketing to ensure that they meet all regulatory requirements.

For More Information

• Using Dietary Supplements Wisely
• Know the Science: How Medications and Supplements Can Interact
• Know the Science: How To Make Sense of a Scientific Journal Article

Key References