The present study was undertaken to examine the protective influence of the alcoholic leaf extract of Hibiscus sabdariffa
(Linn) Malvaceae (an indigenous edible medicinal plant used in Ayurvedic and traditional Medicine in India, China and Thailand) on oxidative stress during ammonium chloride induced hyperammonemia by measuring the extent of oxidative damage as well as antioxidant status. The levels of tissue (liver and kidney) lipid peroxides and the antioxidants; superoxide dismutase, catalase, reduced glutathione and glutathione peroxidase were studied in hyperammonemic rats.Hyperammonemia was induced by daily intraperitoneal injections of ammonium chloride at a dose of 100mg/kg body weight for 45 days. Decreased levels of tissue lipid peroxidation accompanied with increased antioxidant levels inhyperammonemic rats were observed during oral administration of HSEt (250mg/kg body weight), which clearly shows the antioxidant property of HSEt. The study of induction of the antioxidant status is considered to be a reliable marker for evaluating the antiperoxidative effect of the medicinal plant. Our present findings show the protective role of HSEt against lipid peroxidation and suggest that HSEt possesses antioxidant potential that may be used for therapeutic purposes. The exact mechanism of action of the extract still has to be investigated and the isolation of its active constituents remains to be done.