The efficacy and safety of itraconazole oral solution and a combination of amphotericin B capsules plus nystatin oral suspension were compared in the prophylaxis of fungal infections in neutropenic patients. In an open, randomized, multicentre trial, 144 patients received itraconazole oral solution 100 mg bd, and 133 patients received amphotericin B 500 mg tds plus nystatin 2 MU qds. Overall, 65% of itraconazole-treated patients were considered to have had successful prophylaxis, compared with 53% in the polyene group. Proven deep fungal infections occurred in 5% of patients in each group. Fewer patients receiving itraconazole than amphotericin plus nystatin had superficial infections (3 versus 8%; P = 0.066). This trend in favour of itraconazole was seen in patients with profound neutropenia (neutrophil count <0.1 x 10(9) cells/L at least once) or prolonged neutropenia (neutrophil count <1.0 x 10(9) cells/L for >14 days). The median time to prophylactic failure was longer in the itraconazole group (37 days) than in the polyene group (34 days). The number of patients with fungal colonization (nose, sputum, stool) changed more favourably from baseline to endpoint in the itraconazole group than in the polyene group. Both treatments were safe and well tolerated; however, patients receiving amphotericin plus nystatin had a higher incidence of nausea and rash. In conclusion, itraconazole oral solution at doses of 100 mg bd and oral amphotericin B plus nystatin have similar prophylactic efficacy against fungal infections in neutropenic patients. On the basis of reduced incidence of superficial fungal infections, fungal colonization and specific adverse events, itraconazole may be the preferred treatment.