Septicemia caused by anaerobic bacteria is indistinguishable from septicemia caused by aerobic bacteria. High age, origin in the gastrointestinal or genitourinary tract, malignancies and surgery or invasive, diagnostic procedures are indicative of anaerobic etiology. Between 5% and 15% of all septicemias are anaerobic. Benzylpenicillin is active against most anaerobic bacteria, and nitroimidazoles, clindamycin and chloramphenicol are dependable drugs in the treatment of bacteroides septicemias. Surgical drainage and debridement are of major importance, and proper measures to prevent circulatory failure are mandatory. Hyperbaric oxygen therapy may have a dramatic effect. The use of corticosteroids and endorphin antagonists is controversial. Exchange transfusions have been attempted, but further clinical trials are necessary to establish their place in the management of anaerobic septicemia.