Cefoxitin was administered by the intramuscular route to 102 patients who had infections of mild or moderate severity. The assessment of clinical and bacteriologic outcome was derived from data for 79 patients. Assessments of tolerance and safety were made for all patients who received 1 g of cefoxitin diluted in 1 ml of 0.5% or 1.0% lidocaine four times daily. Cure or improvement occurred in 45 of 47 patients with skin or soft tissue infections, in all of 16 patients with lower respiratory tract infections, and in 10 of 12 patients with urinary tract infections. One patient developed acute tubular necrosis. Eosinophilia was seen in 7% of patients treated with cefoxitin. The intramuscular preparation was not painful to 96% of the patients. Cefoxitin given by the intramuscular route can be used as an alternative to intravenous cefoxitin for treatment of mild or moderate infections, for continuation of treatment when the intravenous route is not appropriate, and for treatment of ulcers of polymicrobial etiology on ischemic extremities or on extremities of diabetic patients.