Orthosiphon stamineus Benth (Family: Lamiaceae) or locally known as Misai Kucing
has been widely used in Malaysia for treating kidney problems, gout, and diabetes. This study
aims to evaluate the possible toxic effect after following fourteen days oral administration of
methanol extract of O. stamineus in female Sprague Dawley (SD) rats. Control groups were
treated orally with distilled water (vehicle) while the four test groups were treated up to fourteen
days with 0.5 g/kg, 1 g/kg, 3 g/kg and 5 g/kg body weight of methanol extract of O. stamineus
respectively. Toxicity of the methanol extract of O. stamineus was evaluated by the incident of
lethality, side-cage observation and blood serum biochemical parameters. No lethality or adverse
toxic signs were seen during the experimental period. A significant decrease in several serum
biochemical parameters i.e. AST and ALT and increase in liver weight was observed in young
female SD rat after being fed fourteen days with methanol extract of O. stamineus. No delayed
toxic effect and lethality was observed in all rats during fourteen days of recovery period. In
conclusion, methanol extract of O. stamineus within these range and treatment duration would
not cause any severe toxic effects and organ damages in rats.