Generic Name: kava

Other Names: ava pepper, awa, intoxicating pepper, kao, kawa, kew, piper methysticum, sakau, tonga, yagona

Drug Class: Herbals

What is kava, and what is it used for?

Kava, also known as kava kava, is an herbal product extracted from Piper methysticum, a plant native to the Western Pacific islands. The name kava means “intoxicating pepper” and originates from the Polynesian word “awa.”

Kava has been used by the islanders for centuries as a ceremonial drink during rituals and is also offered to guests in social gatherings. Kava is used medicinally for its muscle relaxing and mood-elevating properties to treat insomnia, anxiety, and other related disorders.

The traditional way of preparing kava drink is by chewing or grinding the kava roots and rhizomes into pulp, blending it with water and filtering before drinking it. In the U.S. and western countries, solvents such as acetone or ethanol may be used in kava extraction. Kava products are available over the counter (OTC) in the U.S. as standardized liquid extracts, tinctures, dried powder, and tablets.

The therapeutic effects of kava come from kavalactones, a mixture of compounds found in kava roots. Kavalactones are believed to have sedative, anti-anxiety (anxiolytic), antistress, pain-relieving (analgesic), local anesthetic, anticonvulsant and neuroprotective properties. Kavalactones appear to work directly on muscles as a relaxant, and kava may relieve anxiety by altering the levels and activity of chemicals (neurotransmitters) that nerves use to communicate with each other, however, there is no conclusive evidence for these mechanisms of action.

Kava may work in the following ways on the central nervous system:

  • Reduce levels of glutamate, the primary excitatory neurotransmitter
  • Enhance the activity of dopamine, the neurotransmitter involved in movement, memory, and pleasure
  • Enhance the activity of the major inhibitory neurotransmitter, gamma-aminobutyric acid
  • Inhibit monoamine oxidase, the enzyme that breaks down neurotransmitters, thereby increasing the levels of dopamine and serotonin

Kava has the potential for abuse and addiction because of its mood-elevating properties. Another major concern is liver toxicity with kava intake, and about 35 cases of severe liver toxicity have been reported in Europe and the U.S. In the past few years. Kava sale was restricted or banned in Europe, Canada, and Australia for some period because of reported liver toxicity and in 2002, the US FDA released an advisory notifying consumers about the potential for liver injury.

A direct causal relationship with kava has been difficult to establish in most of the reported cases of liver injury, and the Pacific islanders who traditionally use kava do not have a higher incidence of liver disease. Kava is metabolized by the liver, but it is not clear if the toxicity results from kava’s metabolites or from accumulation of other drugs, because the same liver enzymes metabolize most other drugs. Some blame the toxicity on the poor quality of kava supplements available in Western countries or using it in combination with alcohol.

Suggested uses of kava include:


  • Do not take kava if you are hypersensitive to any of the components in the kava formulation.
  • Do not take kava if you have liver inflammation (hepatitis) or a history of hepatitis, or any type of liver disease.
  • Do not take kava if you have Parkinson’s disease, may make the condition worse.
  • Do not take if you are pregnant or breastfeeding.
  • Do not administer kava to a child.
  • Do not take concurrently with drugs that are metabolized by the liver.

What are the side effects of kava?

Common side effects of kava include:

  • Acute liver inflammation (hepatitis)
  • Liver toxicity (hepatotoxicity)
  • Liver failure
  • Allergic skin reactions
  • Gastrointestinal upset
  • Headache
  • Dizziness
  • Drowsiness
  • Enlarged pupils
  • Eye movement disorder (oculomotor equilibrium disturbances)
  • Visual focusing (accommodation) disturbances
  • Motor reflex impairment
  • Parkinsonism

Side effects from chronic use include:

Call your doctor immediately if you experience any of the following symptoms or serious side effects while using this drug:

This is not a complete list of all side effects or adverse reactions that may occur from the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may also report side effects or health problems to the FDA at 1-800-FDA-1088.


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What are the dosages of kava?

There is insufficient reliable information on what might be an appropriate dose for kava.

Suggested Dosing:

Anxiety disorders

  • 70% standardized extract: 100 mg orally three times daily
  • Kava-lactones: 60-120 mg/day orally
  • Root tea: 1 cup orally one to three times daily; 2-4 g root/150 ml water

Benzodiazepine withdrawal, prevention

  • 70% standardized extract
  • Initial: 50 mg orally once/day, THEN
  • Titrate up over 1 week while tapering benzodiazepine over 2 weeks
  • No more than 300 mg/day titrated over 1 week


  • Kava-lactones: 180-210 mg orally at bedtime


  • Kava has a calming and mood-elevating effect, which may lead to kava abuse, tolerance, addiction, and overdose.
  • Kava overdose may cause abdominal cramps, difficulty breathing, weakness, unsteady gait, slurred speech, and impairment of cognitive function. Long-term high doses of kava are toxic to the liver and may lead to hepatitis, cirrhosis, liver failure, and death. Chronic kava use also may affect the skin, making it flaky, dry and yellowish.
  • Kava withdrawal symptoms may include rebound anxiety, headache, nausea, fatigue, and cravings for the substance.
  • Kava overdose and withdrawal symptoms may be treated with symptomatic and supportive care, however, extensive liver damage may require liver transplant. The skin condition appears to resolve with discontinuation of kava.

What drugs interact with kava?

Inform your doctor of all medications you are currently taking, who can advise you on any possible drug interactions. Never begin taking, suddenly discontinue, or change the dosage of any medication without your doctor’s recommendation.

  • Kava has no known severe interactions with other drugs.
  • Serious Interactions of kava include:
    • Sedative medications (central nervous system [CNS] suppressants)
  • Kava has moderate interactions with at least 29 different drugs.
  • Mild Interactions of kava include:

The drug interactions listed above are not all of the possible interactions or adverse effects. For more information on drug interactions, visit the RxList Drug Interaction Checker.

It is important to always tell your doctor, pharmacist, or health care provider of all prescription and over-the-counter medications you use, as well as the dosage for each, and keep a list of the information. Check with your doctor or health care provider if you have any questions about the medication.

Pregnancy and breastfeeding

  • Do not take kava if you are pregnant or breastfeeding, it is unsafe.

What else should I know about kava?

  • Short-term use of kava in recommended use may not harm adults with normal liver and who are not taking other medications metabolized by the liver.
  • Do not take kava without first checking with your healthcare provider.
  • Use kava exactly as per label instructions. Do not take for a prolonged period.
  • Do not take kava before driving or operating heavy machinery, kava may impair your mental and physical abilities.
  • Store safely out of reach of children.
  • In case of overdose, report to Poison Control.
  • Herbal products often contain many ingredients. Check labels for the components in the kava product you choose.
  • Kava is marketed as an herbal supplement and is not regulated by the FDA. Products may differ in formulations and strengths, and labels may not always match contents; exercise caution in choosing your product.
  • In 2002, the U.S. FDA released an advisory notifying consumers about the potential for liver injury.


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Kava (kava kava, Piper methysticum) is an herbal product used medicinally for its muscle relaxing and mood-elevating properties to treat insomnia, anxiety, and other related disorders. Common side effects of kava include acute liver inflammation (hepatitis), liver toxicity (hepatotoxicity), liver failure, allergic skin reactions, gastrointestinal upset, headache, dizziness, drowsiness, eye movement disorder, visual focusing (accommodation) disturbances, motor reflex impairment, and Parkinsonism. Kava has a risk of abuse, tolerance, addiction, and overdose. Do not use if pregnant or breastfeeding.

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Medically Reviewed on 8/22/2022