General pharmacological investigations were conducted to elucidate various pharmacological activities of the crude extract of Antidesma acidum (Mamao) in animal models or bioassays including guinea-pig, rat and mice. The investigations covered the test on central nervous system, cardiovascular system, respiratory system, hematological system, and gastrointestinal system and were performed in conscious or anesthetized animals and some isolated organ preparations. The crude extract of Antidesma acidum, fed to rats orally once daily for 7 days, were significantly at the doses of 60mg, and 120mg/kg/BW increased the white blood cells (WBC) but not increased other blood components. Rotarod test, in mice given Antidesma acidum extract by intraperitoneal route at the dose of 30mg, 60mg, and 120mg/kg/BW could maintain their equilibrium for at least 1 min on the rotating rod in each of three successive trials. Antidesma acidum pretreatment did not prolong barbiturate induced sleeping time in rats. The crude extract of Antidesma acidum at the dose of 120mg/kg/BW tended to decrease the distance of charcoal movement from duodenum to ileo-caecal junction in conscious rats. The crude extract of Antidesma acidum were significantly at the concentrations of 100 µg, 200 µg and 400 µg/ml decreased the contraction of isolated ileum induced by 1x10-6M of methacholine. The crude extract of Antidesma acidum at the concentrations of 50 µg, 100 µg , 200 µg and 400 µg/ml did not significantly affect the contractions of isolated rat right auricle, as well as the contraction of isolated rat aorta induced by 1x10-6 M of noepinephrine and the contraction of isolated guinea-pig trachea induced by 1x10-6 M of histamine. The results indicated that pharmacological effects of Antidesma acidum increasing of the white blood cells (WBC), and decreasing of intestinal contraction by which the mechanisms to be further studied. The effects of Antidesma acidum on heart, aorta and trachea were not clearly observed