77 unselected adult patients with acute myeloblastic leukaemia (AML), including practically all AML patients from an area with 1.9 million inhabitants, were randomized for either (1) 5 days pretreatment with 1-asparaginase and prednisolone followed by a combination of rubidomycin and cytosine arabinoside (ARAP), or (2) treatment with a combination of rubidomycin, cytosine arabinoside and prednisolone without 1-asparaginase pretreatment (RAP). Complete remission was induced with ARAP in 12 patients (31%) and with RAP in 13 patients (34%). Thus pretreatment with 1-asparaginase did not improve the therapeutic response. The overall remission frequency was significantly higher below the age of 60; 50% compared to 13% above this age. Side-effects such as liver dysfunction, nausea and vomiting were more common in patients pretreated with 1-asparaginase. Sterilization of the gut did not improve the remission frequency with either regime.