Fourteen cases of nonclostridial anaerobic infections of soft tissues caused by peptococci, peptostreptococci, bacteroids or their combinations with E. coli, Proteus, and Staphylococcus aureus were studied. They are characterized by a rapid spread of serous-suppurative inflammation and the causative agents in loose fibrous connective tissue of subcutaneous adipose tissue (cellutitis), surface fascia (fasciitis), or skeletal muscles (myositis). Dissolution of intercellular structures of the connective tissue, extensive necroses, mild leukocyte reaction, and a wide peripheral zone of toxic edema are observed in the focus of inflammation. This is due to a high toxicity and enzymatic activity of the causative agents. Gas formation is observed when anaerobes are combined with E. coli.