A 48-year-old woman treated with oxyphenbutazone developed fever, gastrointestinal disturbances, mucocutaneous reactions, leukopenia, eosinophilia and thrombocytopenia. Bone marrow biopsy showed granulomatous lesions. Following withdrawal of the drug, all signs and symptoms subsided and the blood changes and the bone marrow biopsy normalized. The granulomatous reaction in the bone marrow is considered to be a hypersensitivity manifestation of oxyphenbutazone.