A 69-year-old woman with idiopathic thrombocytopenic purpura, who was regul
arly followed and treated with prednisolone and danazol, was admitted to ou
r hospital because of shortness of breath. Chest roentgenogram showed a lar
ge amount of left-sided pleural effusion. Gram-positive branching rods, sub
sequently identified as Nocardia farcinica, were isolated from the fluid. A
ntibiotic treatment together with pleural drainage with an intercostal cath
eter resulted in complete remission of pyothorax. Pulmonary nocardiosis is
a rare disease, but recognition of the disease in immunocompromised patient
s and the prompt initiation of appropriate treatments based on isolation of
the pathogen can lead to a successful outcome.