During a period of 32 months (August 1986 until April 1989) 108 patients (74 women, 34 men; mean age 53 years) with neoplastic diseases (59 patients with solid tumors, 45 patients with lymphomas, two patients with acute leukaemias, one patient with chronic myelogenous leukaemia, one patient with aplastic anaemia) were studied in the Department of Internal Medicine of the University Erlangen-Nuremberg. Most were treated with a cytostatic chemotherapy. In order to prevent a mycotic infection in these immunocompromised patients, itraconazole, a new broad-spectrum antimycotic drug of the azole group, was given in an oral dosage of 100 mg day-1 (mean duration of prophylactic treatment 24 months). Localized Candida infections involving the oropharynx and the female genital organs were diagnosed in 16 patients (14.8%). Candida endophthalmitis occurred in one patient (0.9%). The serum concentration of Candida antibodies was significantly elevated in one patient (0.9%) without evidence of fungemia. Itraconazole had to be discontinued in four cases (3.7%) due to minor side effects of the drug (nausea, stomach complaints). Itraconazole appears to be a safe and effective antimycotic drug in long-term use in neutropenic patients.