When taken consistently for longer than a month or in higher doses (1,000 mg/day or more), kava use is more likely to result in liver damage or dysfunction, liver enzyme impairment, and, in rare cases, death.[1][2][3][4][5][6] Some experts suggest that reports of liver damage with kava use may be unfairly blaming kava, when other factors were actually at play.[2][7][4] While no controlled trials using standardized formulations have reported liver injury, not all trials assess the participants for this adverse event.[8][9] Until kava’s potential for liver damage has been fully and accurately assessed, caution is advised. See our additional FAQ below,What long-term side effects are associated with kava?, to learn more details.
Kava’s reported side effects include headaches, sleepiness, sedation, diarrhea, and skin rashes.[10][11][12][13][14] Observational research suggests an association between kava use in pregnancy and low infant birth weight, but kava has not been established as a direct cause of the outcome.[15] Kava powder taken in very high doses (more than 100 times the dose at which liver damage has been observed) may result in a state similar to alcohol intoxication.[2][16] Long-term kava use has also been associated with negative outcomes similar to those seen in alcoholism, such as increased liver enzymes, which could suggest liver injury, and reductions in the number of lymphocytes, which could negatively impact immune response.[17][16] The latter finding is particularly interesting, because reducing anxiety and/or stress has generally been associated with improvements in immune response. Combining kava with alcohol may also magnify the effects of both substances.[18][19]