Aclacinomycine-A (ACM), a new anthracycline derivative, was administered intravenously to 50 patients in doses of 10-30 mg/m2/day for periods of 6 to 30 days. Among the 45 patients who could be assessed, 17 were suffering from acute myeloid leukaemia, 19 from acute lymphoid leukaemia and 9 from non-hodgkin lymphoma. The results confirmed those first published by the authors in 1978 and led them to propose new measures aimed at reducing the toxicity of ACM. Depending on the dosage, complete or partial (more than 50%) remissions were obtained in patients with acute myeloid leukaemia. In the 19 patients with acute lymphoid leukaemia, complete remission was observed in 2 and partial remission in 2. Among the 9 patients with non-hodgkin lymphoma, there was 3 complete and 1 partial remissions. ACM did not produce alopecia and, as predicted by the authors' experimental study on hamsters, did not have major cardiac toxicity. The gastrointestinal toxicity, which had forced a reduction of the total dose in the first trial, proved moderate, even with normal dosage.