Background: Kawasaki disease (KD) is an acute febrile systemic vasculitis most commonly seen in children under the age of 5 years old. High-dose aspirin is often administered, but the duration of such treatment varies. Many centers reduce the aspirin dose once the patient is afebrile, even before treating said patient with IVIG. However, a randomized controlled trial regarding high-dose aspirin in the acute stage of KD has not previously been carried out.