Diabetic foot infections, a frequent and serious cause of morbidity in patients with diabetes mellitus, are caused by anaerobic and aerobic bacteria. Given the fact that seriously impaired host defense factors are almost always present in these patients, bactericidal agents with a broad spectrum of antimicrobial activity are required for their treatment. Seventy-four patients with diabetic foot infections were treated with parenteral sulbactam-ampicillin (1.5 g, q.i.d.). All patients were followed-up prospectively in order to determine the efficacy and safety of sulbactam-ampicillin. The mean duration (+/- SD) of treatment in patients with osteomyelitis (n = 49) and soft tissue infections (n = 25) was 41 +/- 5 and 14 +/- 3 days, respectively. Infected limbs were amputated at various levels in 14 patients (19%). Clinical cure rates were 86% and 100% in patients with osteomyelitis and with soft tissue infection, respectively. The most frequent side effect was diarrhea and observed in 10 patients (14%). The results of the present study indicate that sulbactam-ampicillin is safe and effective in the treatment of diabetic foot infections.