Since untreated or delayed treatment of Kawasaki's disease is associated with the development of coronary artery aneurysms, urgent treatment with high-dose IVIG (total dose 2g/kg) was given in conjunction with anti-inflammatory doses of aspirin. This led to rapid resolution of fever and normalization of C-reactive protein (CRP) (within 48h). While IVIG is undoubtedly effective in Kawasaki's disease the mechanism of action is unclear. For maximum benefit, treatment should be administered within 10 days of onset of fever.