Abstract:According to the relationship between dosage and effect ,the time course of analgesic was determined after oraladiministration of Xiaohuoluo Pills to mice. Based on this experiment ,contrasting the commercial pills with the refe-rence preparation ,the bioavailability of Xiaohuoluo Pills was studied. It was shown that the bioavailability of differentbatches of product from the same factory was different. This method was good for the study of compound preparationsof Chinese materia medica.