A 3-year-old boy, who developed the signs and symptoms characteristic of Kawasaki disease, is described. The child also had an 8 cm tender hepatomegaly. Hydrops of the gallbladder could not be shown. Liver biopsy showed marked infiltration of inflammatory cells, including neutrophil and eosinophil leucocytes in the portal tracts involving the periphery of the portal arteries and veins, and acute inflammation of the bile ducts with neutrophil and eosinophil infiltration of the walls. Overt cholangitis has been described only once before in Kawasaki disease, when a viral agent was suggested as being important in the pathogenesis. Although the clinical and laboratory findings in cases of Kawasaki disease clearly suggest an acute infection--as they did in this case--no aetiological agent has yet been incriminated. The possibility of a drug-induced auto-allergic or hypersensitivity state is considered. Evidence for such a state includes a history of drug administration, pathological findings similar to peri-arteritis nodosa--a condition often associated with a hypersensitivity state--the presence of eosinophils in the lesions and a response to treatment with aspirin, a drug known to ameliorate hypersensitivity states.