Methacolimycin capsule containing 100 mg Sod. Colistin Methasulfonate demonstrated good effects against bacillary dysentery and carrier state of healthy persons in single use, although asubsidance of diarrhea and normalization of stool nature were a little retarded inspite of its excellent in vitro effects. In treatment of antifiotic resistant bacillary dysentery, an urgent problem, a Telatively small dosis of 400 mg Sod. Colistin Methasulfonate were effective almost without any side effects. It was conluded that Methacolimycin was a valuable therapeutic agent against bacillary dysentery, although some problems such as fluctuation of effects and reappearance of bacilli in stool in case of TC-, CP-and SM-sensitive strains were still left unsolved.