Kawasaki Disease (KD) is an inflammatory vasculitis of unknown etiology that affects infants and children and can cause coronary artery aneurysms. Standard therapy consists of 2 gm/kg of intravenous immune globulin plus high-dose aspirin in the acute phase, and low-dose aspirin in the convalescent phase. Some children do not respond to this therapy, and some children go on to develop coronary artery aneurysms in spite of aggressive treatment. This led to the design of this randomized controlled trial to compare a single dose of intravenous steroids vs. placebo on the background of standard therapy. Recruitment began in December, 2002 and ended in December, 2004 with nearly 200 patients randomized.