Intramuscular administration of 25 mg/kg of matrine decreased carrageenin-induced hind paw edema in rats. Daily dose of 15 and 25 mg/kg of matrine for 8 days also reduced ear inflammation in rats caused by croton oil. Adrenolectomy did not alter the anti-inflammatory effect of matrine in mice. Matrine at intraperitoneal or oral doses of 20 and 30 mg/kg inhibited yeast-provoked elevation of body temperature in rats. The antipyretic effect of matrine is believed to be mediated by dopamine release or through dopominergic receptor blockade.