In the literature to date, there have been 44 confirmed cases of infection with the Dysgonic Fermenter-2 (DF-2) bacterium. DF-2 infections appear to demonstrate a strong association with dog bites (or recent exposure to dogs) and have a predilection for patients with defective host defenses although immunocompetent individuals are also susceptible. Recently, the first two cases of documented DF-2 infection following cat bite have been reported. Of the cases reported, 42 of the 44 blood cultures grew DF-2. In one of the two cases where blood culture failed to grow DF-2, the bacterium was isolated at the time of operation from an infected myxoma of the tricuspid valve. In the other case, the organism was isolated from the eyelid margin of a case of angular blepharitis. Peripheral blood smears also afford an effective and practical clinical tool for early diagnosis; 9 of 10 patients for whom smears were done tested positive. This paper reviews the epidemiologic, microbiological, and clinical features of this relatively new illness and also offers general guidelines to physicians for clinical management. Health professionals, especially those providing care for high risk groups, should be alerted to this potentially fatal infection.