ABSTRACTA 46‐year‐old housewife was treated orally with 5‐fluorocytosine (5‐FC). She was almost cured at 15 weeks after the administration. Under histological and electron microscopical examination, spores in the lesions were observed to be markedly decreased in number, and all of them had suffered a change of shape or had been destroyed. At the end of 33 weeks, however, the patient had a complete