The association between invasive Clostridium septicum infection and co
lorectal carcinoma is examined by the presentation of three cases and
a review of the literature. In the first two cases the patients presen
ted with nontraumatic metastatic clostridial gas gangrene. In the thir
d case a patient with chemotherapy-induced myelosuppression from conco
mitant multiple myeloma had a necrotizing transmural infection of the
right colon. The apparent portal of entry of Clostridium septicum was
an occult carcinoma of the ascending colon. The increasing evidence fo
r a strong link between this organism and some cases of neutropenic en
terocolitis is reviewed.