Kava ( Piper methysticum Forst. f., Piperaceae), prepared as the traditional aqueous infusion, was tested in the rat for possible effects on liver function tests. Extracts were administered in daily dosages of 200 or 500 mg of the active kavalactones/kg for two or four weeks. Sera were assayed for four enzymes that are markers of liver toxicity and liver homogenates for malondialdehyde formation that indicates changes in lipid peroxidation. The data showed that none of the enzymes, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and lactate dehydrogenase, nor malondialdehyde were elevated, in fact in some cases they were significantly reduced, suggesting the lack of a toxic effect by kava on the liver.