A VARIETY of serious infections due to Lancefield group G Streptococcus have been reported.1-6 These infections often have occurred in patients with underlying debilitating conditions. We describe a chronic alcoholic patient with group G streptococcal septic arthritis, who had a complicated course despite high-dose penicillin therapy. The case is compared with two previously reported cases of group G streptococcal arthritis. Report of a Case A 67-year-old man, who was a chronic alcoholic, fell down a flight of stairs five days before hospitalization. He sustained multiple skin abrasions and experienced pain and swelling of his left knee. He sought medical help because of persistent left-knee swelling associated with diaphoresis. He had no other underlying medical problems. His temperature was 37 °C. He had multiple skin abrasions without evidence of infection. He had poor dentition and a tender, warm, and swollen left knee. On laboratory examination, peripheral leukocyte count was 18,000/cu