Peripheral blood stem cells can reconstitute bone marrow function after high-dose chemo-/radiotherapy. We describe 17 patients treated with a three-day course of chemotherapy consisting of cyclophosphamide or ifosfamide and etoposide (malignant lymphoma and germ cell tumor) or a one-day course of 5-fluorouracil, epidoxorubicin and cyclophosphamide (breast cancer), followed by the administration of recombinant human granulocyte colony-stimulating factor (G-CSF). Maximum numbers of peripheral blood stem cells were recruited on day 9-10 of the G-CSF administration with 0.1 x 10(9)/l CD34+ cells (median; range 0-0.36). The total number of peripheral stem cells harvested with two-three leukaphereses was 40 x 10(4)/kg CFU-GM (4-257) or 8 x 10(6)/kg CD34+ cells (1-39). Ten patients with malignant lymphoma or solid tumours received high-dose chemotherapy followed by bone marrow and peripheral stem cell infusion (n = 7) or peripheral stem cell infusion alone (n = 3). The recovery of granulocytes, platelets and reticulocytes after peripheral stem cell infusion, in addition to or instead of bone marrow, was markedly accelerated compared with the infusion of BM alone. The accelerated haemopoietic recovery was associated with a reduction in platelet and red blood cell transfusion, reduction in fever periods and earlier discharge from hospital. Peripheral stem cell transplantation may become an important alternative to autologous bone marrow transplantation. This transplantation technique may also allow application of multiple-cycle intensive chemotherapy.