One hundred and twenty-six patients were treated for 137 episodes of fungal infection with liposomal amphotericin B (AmBisome) at 43 investigational centres. Among the patients were 72 with malignancies, 17 organ transplant recipients, 20 patients with immunological disorders and 17 others. AmBisome treatment was instituted after toxicity from previous amphotericin B treatment in 49 cases, nephrotoxicity or renal insufficiency in 40 and failure of previous antifungal treatment in 41. One hundred and eight episodes were clinically evaluable; among these 52 were caused by Candida spp. and 34 by Aspergillus spp. Ninety-nine patients were treated for at least eight days with a maximum dose of 0.7-5 mg/kg/day. Among 64 cases with proven invasive fungal infection 58% were cured. Fungi were eradicated in 35 of 54 (65%) mycologically evaluable cases. The cumulative dose was 3.2 +/- 3.2 (mean +/- S.D.) in cases where fungi were eradicated in comparison with 3.3 +/- 2.3 g in cases where fungi persisted. The eradication rate was 83% for Candida spp. compared with 41% for Aspergillus spp. (P less than 0.01). Among 24 cases with presumptive invasive fungal infections 14 (58%) were cured. Candida spp. were eradicated in seven of ten of these cases. Among 11 cases with superficial fungal infections eight were cured and three improved. Candida spp. were eradicated in four of five patients. It is concluded that AmBisome is an effective antifungal agent in a majority of patients with invasive or superficial fungal infections.