In order to determine the quality of marketed gastrointestinal drugs (gel & suspension), 40 commercial samples were purchased from different cities in Taiwan during 1994. The specimens were subjected to microbial limits test including total aerobic microbial count, for Pseudomonas aeruginosa and Escherichia coli. The results showed that 11 of products (27.5%) were contaminated with total aerobic microbial counts higher than 100/mL Furthermore, 2 samples were found to be contaminated with Pseudomonas aerugthosa and 2 samples contaminated with Escherichia coli.