A patient with eosinophilic cholecystitis and accompanying eosinophilic appendiceal inflammation, eosinophilic pericarditis, and peripheral eosinophilia is described. Review of the nine previously reported cases of eosinophilic cholecystitis suggests that this is the first case with closely associated eosinophilic appendiceal inflammation and pericarditis as manifestations of a systemic hypereosinophilic syndrome. The possible etiologic role of cephalosporin hypersensitivity is discussed.