The multiple dose pharmacokinetics of a solution of itraconazole given orally were measured in an open study of 20 patients undergoing remission induction chemotherapy for acute myeloid leukaemia. Patients were given itraconazole 5 mg/kg od, 2.5 mg/kg bd, 2.5 mg/kg odor 1.25 mg/kg bd. The mean daily dose of itraconazole was 407 mg for patients receiving 5 mg/kg/day and 148 mg in patients receiving 2.5 mg/kg/day. Mean concentrations of 493 and 495 μ/L were achieved on day 8 in patients who received 5 mg/kg/d od or 2.5 mg/kg bd itraconazole respectively. However, mean concentrations were significantly lower for those who received 2.5 mg/kg od itraconazole being 110 μg/L on day 8. Mean areas under the serum-concentration time curves were also markedly higher in patients receiving 5 mg/kg/day than in those receiving 2.5 mg/kg/day itraconazole and were 22,382 and 5615 μg.h/L on day 15 respectively. These findings suggest that the serum concentrations attained with an oral solution of 5 mg/kg itraconazole either once daily or in two divided doses are suitable for antifungal prophylaxis in patients receiving chemotherapy for acute myeloid leukaemia.