Phase II of the trial began enrollment of 549 patients in May 1986 and ended enrollment in November 1989. Two hundred and seventy six children were randomized to receive 400 mg/kg of intravenous gamma globulin over four consecutive days. Two hundred and seventy-three received a single infusion of 2 g/kg of body weight over 10 hours. Both treatment groups received 100 mg/kg of aspirin per day through day 14 and then 3 to 5 mg/kg per day. The primary outcome variables were the presence or absence of coronary artery abnormalities evident at the two week and seven week follow-up examinations. Echocardiograms were obtained for 523 children at the two week visit and for 520 children at the seven week visit.