The efficacy and safety of fluconazole in the treatment of oesophageal candidiasis in patients with the acquired immunodeficiency syndrome (AIDS) was assessed in 36 patients. Fluconazole, 200 mg orally, was given on the first day, followed by 100 mg daily for 4 weeks. Clinical and mycological evaluation was performed in 31 patients at the end of treatment and 24 were also assessed after 8 weeks of starting treatment. In 1 patient fluconazole was discontinued, 5 patients were lost to follow-up and 6 patients died during the study. Clinical and mycological cure was achieved in all patients; in 31 of 36 patients the clinical picture resolved within a week. The cure was confirmed in 27 patients by oesophagoscopy. Two patients relapsed 1 month after stopping fluconazole but the reinstitution of therapy achieved cure. Asymptomatic fungal oropharynx colonization was evident in about 40% of patients during treatment and follow-up period. Fluconazole was well tolerated by all patients but mild to moderate increase of liver enzymes values occurred in 16. Treatment had to be discontinued in 1 patient with hepatic tuberculosis because of severe liver function abnormalities, but their relation with the drug was uncertain. Fluconazole is an effective and safe treatment of oesophageal candidiasis in AIDS patients.