Coronary artery aneurysms occur in 15-20 percent of children with the illness. In the past, no treatment had been shown to be effective in preventing this complication. Investigators in Japan began to use IVGG to reduce the aneurysm formation. Preliminary results showing the usefulness of this therapy led to a multicenter trial in Japan in which 400 mg/kg/day of IVGG were given for five days to children also receiving aspirin for the condition. Results of the Japanese trial showed that within 29 days of the onset of the disease, coronary artery dilatation had developed in 42 percent of the aspirin-treated children and in 15 percent of the IVGG and aspirin-treated children.