Subtotal $0.00
Shop Now
Kava is a drink and supplement made from the root of Piper methysticum, a South Pacific plant in the pepper family. It is promoted for relaxation, and kava bars now operate in many US locations. The central safety fact is liver injury: in 2002 the FDA warned that kava-containing dietary supplements may be associated with severe liver injury, and the National Center for Complementary and Integrative Health (NCCIH) still describes rare but sometimes serious or fatal cases. Kava should not be mixed with alcohol or sedatives, and it can affect driving. This guide covers those risks, other side effects and what trials found.
Peptide Labs sells dietary supplements, but it does not sell kava, and none of the product labels in our catalog list it. This article is general information, not medical advice.
Key Takeaways
- Kava products have been linked to rare cases of liver injury, including liver failure and transplants.
- FDA issued a consumer advisory on March 25, 2002, and several countries restricted or removed kava products.
- NCCIH says kava should not be combined with alcohol or sedatives such as benzodiazepines.
- Memorial Sloan Kettering says kava may impair the ability to drive or operate heavy machinery.
- Anxiety trials are mixed: a larger 16-week trial found no benefit over placebo for generalized anxiety disorder.
What is kava?
Kava, also called kava kava, awa, ava pepper or kawa, has been prepared as a drink by Pacific Islanders for thousands of years for ceremonial and medicinal purposes. The root contains compounds called kavalactones, which supplement labels and studies usually measure. Traditional kava is a water-based drink made from the ground root. Supplements are often concentrated extracts in capsules, tablets, tinctures or powders.
In the United States kava is sold as a dietary supplement and as a beverage; in some other countries it is regulated as a drug or herbal medicine. The 2002 FDA advisory noted that kava should be named in the Supplement Facts box and listed other names it may appear under, including ava, awa and intoxicating pepper. Blends sold for sleep or stress can combine kava with other herbs: one product in a 2002 CDC case report also listed hops, German chamomile and passion flower, so check the full ingredient list.
Kava liver damage: what the reports show
Kava liver damage is the reason kava is handled differently from most herbs. The table summarizes the main public health actions and reports.
| Source | Year | What it reported |
|---|---|---|
| FDA consumer advisory | 2002 | Over 25 foreign reports of hepatitis, cirrhosis or liver failure; four transplants; one US transplant |
| CDC MMWR report | 2002 | 11 kava users with liver failure underwent transplantation in Germany, Switzerland and the US |
| NIDDK LiverTox | Updated 2018 | Products labeled as kava linked to acute liver injury that can be severe or fatal |
| NCCIH | 2025 | Rare liver injury, some serious or fatal, from extracts and from water-prepared drinks |
The CDC report described two US cases in detail: a previously healthy 45-year-old woman and a previously healthy 14-year-old girl, both of whom needed liver transplants after using kava supplements. FDA noted that Germany, Switzerland, France, Canada and the United Kingdom had taken actions ranging from consumer warnings to removing kava products from the market. FDA also said liver damage appears to be rare.
Why liver injury happens is still debated
NCCIH explains that the first reported cases involved extracts made with alcohol or acetone, but later cases involved traditional water-based drinks. Proposed explanations include undesirable kava varieties or the wrong parts of the plant, use together with alcohol, adulteration or contamination, individual genetic differences, and large amounts or long use. None has been proven as the single cause, so no product can be assumed to carry no liver risk.
Liver warning signs
The FDA advisory lists symptoms of serious liver disease: yellowing of the skin or whites of the eyes (jaundice) and brown urine. Less specific signs include nausea, vomiting, light-colored stools, unusual tiredness, weakness, stomach pain and loss of appetite. Anyone who has these symptoms while using kava should stop and contact a doctor promptly. FDA advised people with liver disease, or who take drugs that can affect the liver, to consult a physician before using kava at all.
Kava and alcohol, sedatives and driving
Kava and alcohol are a poor combination. NCCIH says kava should not be used with other substances that have sedative effects, such as benzodiazepines or alcohol, and the National Institute on Alcohol Abuse and Alcoholism lists kava kava among herbs whose combination with alcohol may cause liver damage and drowsiness. Memorial Sloan Kettering (MSK) adds barbiturates and other sedatives to the list, notes that kava increased the liver toxicity of acetaminophen in laboratory studies, and advises stopping kava before surgery because it may interact with anesthetics. Our article on ashwagandha and alcohol explains how other herb-alcohol combinations are judged.
Driving is a separate concern. MSK says kava may impair the ability to drive or operate heavy machinery and cites case reports of impaired driving in which kavalactones were the only substance found. A 2022 study in the Journal of Ethnopharmacology compared 20 people at a traditional kava session with 19 controls and found worse performance on one timing-judgment test six hours in. The authors said kava may impair driver safety, though differently from alcohol or cannabis. Do not drive after drinking kava or taking a kava supplement until you know how it affects you, and never after combining it with alcohol.
Kava side effects
Kava side effects reported by NCCIH and MSK include:
- Digestive upset, headache and dizziness.
- Kava dermopathy: long-term heavy use may cause dry, scaly, flaky skin, reddened eyes and temporary yellow discoloration of the skin, hair and nails.
- Memory and tremor: in a 16-week trial, poorer memory and tremor were reported more often with kava than with placebo.
- Pregnancy and breastfeeding: NCCIH says kava may have special risks because of harmful pyrone compounds.
- Kidney or liver problems: MSK advises people with either condition not to take kava.
What the research on anxiety shows
Kava has been studied mostly for anxiety, and the results are inconsistent. NCCIH says kava supplements may help anxiety but may need several weeks, and that kava does not appear to help symptoms of generalized anxiety disorder. Two Australian trials by the same University of Melbourne group show the split:
- A 2013 six-week trial enrolled 75 adults with generalized anxiety disorder; 58 were analyzed. Anxiety scores fell more with a kava extract than with placebo, and liver tests did not differ.
- A larger 2020 phase III trial followed 171 adults for 16 weeks and found no significant difference from placebo. Abnormal liver function tests were significantly more common with kava, although no participant met the criteria for herb-induced liver injury.
Ongoing anxiety deserves an assessment by a health care provider, who can discuss options with known safety records. If you are reading about calming supplements, our guides to L-theanine and valerian root summarize their evidence, and our St John’s wort guide covers another herb with serious interaction warnings. Any supplement you do use should carry an independent testing seal; see third-party tested supplements.
Frequently Asked Questions
Is kava bad for your liver?
Kava products have been linked to rare cases of liver injury, some serious or fatal, and FDA issued a consumer advisory in 2002. People with liver problems should not use it.
Can you drink alcohol with kava?
No. NCCIH says kava should not be combined with alcohol or other sedatives, and alcohol may add to the liver risk.
What are the side effects of kava?
Digestive upset, headache, dizziness, and with long-term heavy use a scaly skin condition called kava dermopathy. Liver injury is rare but serious.
Can you drive after drinking kava?
Memorial Sloan Kettering says kava may impair driving, and case reports describe impaired drivers. Avoid driving after using it.
Is kava kava the same as kava?
Yes. Kava kava is another name for Piper methysticum, along with awa and ava pepper.
Does Peptide Labs sell kava?
No. None of the products in our catalog list kava.
Questions about a label? Contact us or read our Buyer’s Guide. Follow the label and ask a healthcare provider before starting any supplement, especially if you take medicines or are pregnant. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Last reviewed October 2026.
Related guides: St John’s Wort: Drug Interactions, Side Effects and What Research Shows, Valerian Root: Benefits, Sleep Research, Side Effects and Interactions, Liver Cleanse Supplements: What Is Inside, What Research Measured and Safety Risks.