# Kava (Piper methysticum) *Kava kava, ava, ava pepper, intoxicating pepper; *Macropiper methysticum* Miq.; *Piper methysticum* G. Forst.; in pharmacy *Piperis methystici rhizoma** **Known today as.** *Piper methysticum*, a shrub of the pepper family Piperaceae about six feet high, which King’s Dispensatory describes as somewhat resembling bamboo in growth, native and commonly cultivated in the South Sea Islands, with heart-shaped leaves and small flowers on slender spikes. The drug is the peeled, dried rhizome, in Grieve’s description whitish or grey-brown, starchy, with a faint pleasant odour and a bitter, pungent, aromatic taste. Its active constituents, LiverTox records, are the kavapyrones or kavalactones. Kind: Plant Toxic: yes > **Caution.** LiverTox rates kava a well-known cause of clinically apparent liver injury, which “can be severe and even fatal”; its use has been banned or restricted in countries including Germany, Switzerland, France, Canada, and Great Britain, though some dispute the evidence and blame adulterants or other drugs, and some severe cases are convincing. Its abuse potential is low but not absent: a 2024 case report describes a man who, after weeks of escalating use, was admitted after a fall while intoxicated and developed a withdrawal delirium treated with phenobarbital, the first such report its authors knew of. Headache, dizziness, drowsiness, and diarrhoea are its commonest side effects. ## What was it used for? A ceremonial and social drink, and later a medicine for anxiety. LiverTox records that it has been used for centuries as a recreational and ceremonial drink in Oceania, its kavalactones having effects similar to alcohol, “such as relaxation, talkativeness, and euphoria.” Grieve records that the natives drank a liquor from the rhizome “before important religious rites,” and that in Western medicine it had been used against gonorrhoea and other complaints of the genito-urinary tract. ## What does modern science say? The Cochrane review of 2003, of eleven trials in 645 people, found that kava extract reduced anxiety scores against placebo and “appears to be an effective symptomatic treatment option for anxiety,” relatively safe in the short term though more information on long-term safety was needed. The European Medicines Agency’s herbal committee, however, declined any monograph on the rhizome (public statement of 2017): it found toxicological concerns, carcinogenic potential in animals, in relation to one preparation, and noted spontaneous reports of liver reactions, including liver failure leading to transplants and deaths, and the withdrawal of products in some member states, and judged the balance of benefit and risk unfavourable. A 2025 review of 197 records found its role both in liver toxicity and in reducing anxiety still unclear, while kava remains socially, culturally, and economically important to the Pacific Islands. ## Pharmacognosy and toxicology - **kavalactones**: also called kavapyrones, the active constituents **Mechanism.** Not established in the sources read for this entry. **Standing.** There is no European monograph: the European Medicines Agency’s herbal committee declined one (public statement of 2017), judging the balance of benefit and risk unfavourable. Use is banned or restricted in several countries, among them Germany. A Cochrane review (2003) found it effective for anxiety in the short term. ## What lore surrounds it? Grieve reports that continued use in large doses “causes inflammation of the body and eyes, resulting in leprous ulcers; the skin becomes parched and peels off in scales,” and that its effect on the nerve centres is at first stimulating, then depressing. ## What did the older authorities say? **King’s American Dispensatory (1898).** “It was discovered by James Cook, the celebrated explorer, in 1769, in the Tahiti Islands.” The drink was invariably made by chewing the root to a pulp, covering it with water, macerating it a short time, and straining it through a fibre from the bark of a native tree; its taste was said to resemble soap-suds and tannin. ## Sources - Grieve, M. *A Modern Herbal*, “Kava Kava.” As published on botanical.com. - Felter, H. W., & Lloyd, J. U. (1898). *King’s American Dispensatory*, vol. 2, “Piper Methysticum.” Internet Archive, kingsamericandis02kinguoft. - European Medicines Agency, Committee on Herbal Medicinal Products. *Public statement on Piperis methystici rhizoma (Kava-kava)*. EMA/HMPC/450588/2016, 21 November 2017. - European Medicines Agency, Committee on Herbal Medicinal Products. *Assessment report on Piperis methystici rhizoma*. EMA/HMPC/450589/2016, 21 November 2017. - Pittler MH & Ernst E (2003). Kava extract for treating anxiety. *The Cochrane database of systematic reviews*. PMID 12535473. - Economidis G, et al. (2025). Global Perspectives on Kava: A Narrative Systematic Review of the Health Effects, Economic and Social Impacts and Policy Considerations. *Drug and alcohol review*. PMID 40560778. - Cassidy RM, et al. (2024). Kava Withdrawal Treated With Phenobarbital-A Case Report and Literature Review. *Journal of addiction medicine*. PMID 38829029. - LiverTox: Clinical and Research Information on Drug-Induced Liver Injury, “KavaKava.” National Institute of Diabetes and Digestive and Kidney Diseases, updated 2018. NCBI Bookshelf. - European Medicines Agency, Committee on Herbal Medicinal Products. *Public statement on Piperis methystici rhizoma (Kava-kava)*. EMA/HMPC/450588/2016, 21 November 2017. - European Medicines Agency, Committee on Herbal Medicinal Products. *Assessment report on Piperis methystici rhizoma*. EMA/HMPC/450589/2016, 21 November 2017. - Pittler MH & Ernst E (2003). Kava extract for treating anxiety. *The Cochrane database of systematic reviews*. PMID 12535473. - LiverTox: Clinical and Research Information on Drug-Induced Liver Injury, “KavaKava.” National Institute of Diabetes and Digestive and Kidney Diseases, updated 2018. NCBI Bookshelf. --- *Kava.* In *Materia Medica*, edited by B. C. P. Statema. Version 1, revised 2026-10-17. The Thinking Press. https://thethinkingpress.org/materia-medica/kava Historical description, not medical advice.