Results of three consecutive clinical trials of therapy of anaerobic infections in cancerpatients were compared, using doxycycline versus tinidazole, clindamycin versus cefoxitin and tinidazole versus tinidazole plus amikacin.Mixed aerobic and anaerobic infections had a similar response rate when treatment consisted of a specific anti-anaerobic drug as compared to a broader antimicrobial therapy directed against aerobic and anaerobic pathogens.Even when the anaerobic pathogen was resistant to therapy, many patients were cured. Surgical drainage played an important role, but was difficult to assess precisely.