We studied the effects of an intensified induction/consolidation treatment containing fludarabine (ICE/FLAN/FLAN) on the mobilization and collection of peripheral blood stem cells (PBSC) in 31 consecutive untreated acute myeloid leukaemia (AML) patients. The complete remission (CR) rate was comparable to classic inductions (68% after ICE; 84% after ICE-FLAN I). To mobilize PBSC, 19 patients received 10 microg/kg/d of granulocyte-colony stimulating factor (G-CSF) starting at day 13 after FLAN, 13 (69%) of whom were found to be nonmobilizers. When a second G-CSF administration was performed in 10/13 patients mobilization was either not achieved (8/10) or was considered insufficient (<1 x 106 CD34+ cells/kg) (2/10) and all 13 were subsequently submitted to bone marrow harvest. The harvest was considered adequate in 12/13 (92%) patients and autologous BMT (ABMT) has so far been performed in 10/12 cases with a mean of 8.6 x 108/kg nucleated reinfused cells. The median times to neutrophil and platelet recovery after ABMT did not significantly differ from those of two previous series of patients treated with ABMT without fludarabine-containing regimens. Adequate amounts of PBSC were obtained in 6/19 (31%) patients, who were then reinfused. Median times for platelet recovery were significantly longer than in a previous series of 26 AML cases reinfused with PBSC after treatment with the ICE-NOVIA induction/consolidation regimen (125 v 20 d to 20 x 109 plt/l, P < 0.02; 218 v 37 d to 50 x 109 plt/l, P < 0.02). In addition, times for platelet recovery after ICE/FLAN/FLAN were not significantly different from those in a previous group treated with ABMT performed after ICE/NOVIA,without fludarabine. We conclude that fludarabine-containing regimens severely impair mobilization and collection of PBSC in AML patients and seem unsuitable when PBSC autotransplantation is programmed.