The effectiveness of miconazole was evaluated in 37 documented fungal infections, 32 of which were major infections. All patients were receiving therapy for advanced malignancy, with 28 patients having acute leukemia. The overall cure rate was 41% and it was also 41% for major fungal infections. Nine of 22 patients with Candida albicans infections were cured. A total of 183 patients who received miconazole for presumed or documented fungal infection were evaluated for toxicity. Nausea and vomiting and central nervous system toxicity were the most common side effects, occurring in 25 and 16% of the patients, respectively. Overall, the drug was tolerated well, with only four patients requiring the drug to be permanently discontinued because of toxicity.