An intestinal disorder characterized by sudden onset of colic followed by diarrhea; nausea is common, vomiting and fever are usually absent. Generally a mild disease of short duration—1 day or less—and rarely fatal in previously healthy people. Outbreaks of severe disease with high case-fatality rates associated with necrotizing enteritis have been documented in postwar Germany and in Papua New Guinea (pigbel).

In the outbreak setting, diagnosis is confirmed by demonstration of Clostridium perfringens in semiquantitative anerobic cultures of food (10⁵/g or more) or patients' stool (10⁶/g or more), in addition to clinical and epidemiological evidence. Detection of enterotoxin in patients' stool also confirms the diagnosis. When serotyping is possible during outbreaks, the same serotype is usually demonstrated in different specimens; serotyping is done routinely only in Japan and the United Kingdom.