For the investigation on drug adulteration and microbial contamination in Chinese medicine preparation for diabetes, 100 samples were random by collected in Taiwan area from Nov. 1984 to Jan. 1985. The results of thin layer chromatography analysis showed none of the samples was adulterated with acetohexamide, chloropropamide, glibenclamide, tolbutamide, sulfadiazine, sulfadimethoxine, sulfamerazine, sulfamethazine, sulfamethoxazole, sulfathiazole, sulfisoxazole and sulfamethoxypyridazine. But the microbial test indicated wost of the samples were highly contaminated.