A promising development 0/ recent years has been the application of proteolytic enzymes to the therapy of disease in the human. Originally applied directly to the diseased area to efJect a local enzymatic debridement, proteolytic enzyme therapy is now being extended on a systemic basis to widen considerably the scope of its applicability. This report summarizes the current state of knowledge of proteolytic enzymes as therapeutic agents. It indicates those areas where the usefulness of proteolytic enzyme therapy is well established and those areas where the efficacy of such enzyme therapy is less well accepted or under active clinical investigation. Though much has been accomplished already at the clinicallevel, particular stress is placed on the problems which remain to be solved if proper exploitation of this new and exciting area of pharmacology is to be achieved.