A multicenter randomized controlled study was carried out to assess the effectiveness of different, doses and kinds of gamma-globulin in Kawasaki disease. Gamma globulin lowered the incidence of coronary artery abnormalities. The effect of gamma-globulin was dose dependent. The intact type was more effective than the pepsin treated type. To establish the indications for gamma-globulin, a study was made of patients who received neither gamma-globulin nor indomethacin and who, within nine days of onset of illness, satisfied at least four of the following criteria: (1) WBC: more than 12,000/mm; (2) platelet count: less than 35 X 10(4)/mm; (3) CRP: more than 3+; (4) Hct: less than 35%; (5) albumin: less than 3.5 g/dl (6) age: 12 months or less; (7) male sex. This prospective study is continuing. Of 143 children, 73.4% received gamma-globulin, and only two demonstrated small dilatations of the coronary arteries in children who did not receive gamma-globulin. These guidelines seem satisfactory to establish the indications for gamma-globulin in Kawasaki disease.