What is it?
Kava is a South Pacific medicinal plant, Piper methysticum (Sarris et al., 2020). Its active compounds are kavalactones, such as kavain, yangonin, methysticin and dihydromethysticin (van Breemen et al., 2025).
What does the trial evidence say?
- A 2003 Cochrane review of 11 randomised trials (645 people) found kava extract reduced anxiety scores compared with placebo. Side effects in those trials were mild and infrequent, but the authors said long-term safety needed more study (Pittler et al., 2003).
- A larger 16-week trial in 171 people with diagnosed generalised anxiety disorder found no benefit over placebo for the extract tested. Abnormal liver-function tests were significantly more frequent with kava, although no participant met the criteria for herb-induced liver injury (Sarris et al., 2020).
Kava has been linked to liver toxicity (van Breemen et al., 2025). Neither study tells you how strong a particular kava gummy is.
Hidden kava in mushroom gummies
Kava isn’t only in products labelled as kava. A Portland gummy with no active ingredient on its label contained kava extract (van Breemen et al., 2025). Kavalactones were found in other Portland smoke-shop gummies (Correia et al., 2025) and in some Diamond Shruumz products (Rumph et al., 2026).
Sources
- Pittler MH, Ernst E. Kava extract for treating anxiety. Cochrane Database Syst Rev. 2003;2003(1):CD003383.
Eleven randomised trials (645 participants): kava extract reduced anxiety scores versus placebo in pooled analysis; adverse events in the trials were mild and infrequent, with long-term safety needing more study.
- Sarris J, Byrne GJ, Bousman CA, Cribb L, Savage KM, Holmes O, et al.. Kava for generalised anxiety disorder: A 16-week double-blind, randomised, placebo-controlled study. Aust N Z J Psychiatry. 2020;54(3):288-297.
16-week double-blind trial of an aqueous kava extract (120 mg kavalactones twice daily) for generalised anxiety disorder: no significant benefit over placebo. Liver-function test abnormalities were significantly more frequent with kava, though no participant met criteria for herb-induced liver injury.
- van Breemen RB, Simchuk D, Fritzsche B, Huson D, Kuzdzal SA, Ferguson J. Active Constituents of Psilocybin Mushroom Edibles. JAMA Netw Open. 2025;8(9):e2531345.
Tested 12 'magic mushroom' edibles (11 gummies, 1 chocolate) bought at retail shops in Portland, Oregon. None contained psilocybin. Eight contained active ingredients not disclosed on the label: psilocin (3), synthetic tryptamines mipracetin and 4-HO-DET (2), caffeine (1), kava extract (1) and cannabis extract including Δ9-THC (1). Four had no active ingredient detected. Muscimol and muscarine, listed on one label, were not detected in any product.
- Correia MS, Gonzaga MJ, Temple C, Gerona RR. Quantitative analysis of recreational psychoactive mushroom gummies in Portland, Oregon. Clin Toxicol (Phila). 2025;63(4):261-266.
Eight gummy products from seven Portland, Oregon smoke and vape shops, analysed by LC-QTOF-MS. Neither ibotenic acid nor muscimol was found in the two products claiming Amanita muscaria; seven of eight contained psilocin and six contained 4-AcO-DMT. One product labelled psilocybin-free tested positive for psilocybin; one 'nootropic' product contained undisclosed Δ9-THC; kavalactones were also detected.
- Rumph JT, Winquist A, Troeschel AN, Pulver S, Schnall AH, Ebersole J, et al.. Severe Illness Associated with Eating Mushroom-Containing Chocolate Products - United States, January-October 2024. MMWR Morb Mortal Wkly Rep. 2026;75(13):179-184.
CDC/FDA investigation of poisonings linked to Diamond Shruumz microdosing chocolate and other mushroom-containing chocolate products, January–October 2024: 180 cases in 34 states, 73 hospitalised, 38 admitted to intensive care, 29 intubated, 2 deaths. Testing of some Diamond Shruumz products found muscimol, psilocin, kavalactones and other substances in some but not all products.