A total of 622 consecutive patients with acute promyelocytic leukaemia (APL) treated within the Gruppo Italiano per le Malattie Ematologiche dell'Adulto (GIMEMA) group during 1989-97 have been reviewed to assess the clinical effectiveness of all-trans retinoic acid (ATRA) on the incidence of early haemorrhagic deaths and on APL-associated coagulopathy. Of them, 499 were treated with idarubicin plus ATRA (study A) and 123 with Idarubicin alone (study B). In both studies, similar guidelines for supportive treatment were used. Haemorrhagic symptoms were evaluated according to a reproducible score system. Deaths occurring within 10 d of starting treatment were 19 (3.8%) in study A and nine (7.3%) in study B (P = 0.09), with 15 (3%) and five (4.1%) (P not significant) due to haemorrhage. Overall, induction mortality was 7.6% and 16.2% respectively (P < 0.003). In study A, days with platelet counts </= 20 x 109/l or with fibrinogen </= 1 g/L were reduced by about 30%, the haemorrhagic score by 50% and the consumption of blood products by about 40%, and fewer patients were treated with antihaemorrhagic drugs (39% vs. 61%; P < 0.001). On multivariate analysis, early deaths were influenced by blast count at diagnosis > 30 x 109/l (P < 0.001) in both studies, and by a haemorrhagic score of 3 in study A (P < 0.001). Although the reduction of early fatal haemorrhages was not significant, a substantial clinical improvement was evident in terms of reduction of the severity of bleeding symptoms, blood product consumption and overall induction mortality when ATRA was combined with idarubicin.