We commenced a study in September 1981 to investigate the role of high-dose combination chemotherapy in the management of patients with non-Hodgkin's lymphomas who had failed conventional therapy. Fifty patients with diffuse intermediate- and high-grade non-Hodgkin's lymphomas were treated with high-dose combination chemotherapy with autologous bone marrow rescue (ABMT) and have a minimum follow-up of 1 year. Twenty patients had disease that was still responsive to conventional-dose chemotherapy, 15 had achieved a partial response (PR) to first-line therapy, and five were showing PR to salvage therapy after relapse. Twelve of these patients (60%) achieved complete remission (CR) (two following boost radiotherapy) and three patients have nonprogressive masses on computed tomographic (CT) scan as the only abnormality. None of these patients died during the procedure. Twenty-nine patients had disease not responsive to chemotherapy at conventional dosages: 19 had no response to first-line therapy and 10 showed no response to salvage therapy given after relapse. Only three of these patients achieved CR, all of short duration only. Only two patients in this group remain alive more than 2 years after the procedure and both have nonprogressive abnormalities on CT scan. Nine patients (31%) died of sepsis during the procedure. In those patients with disease not responsive to conventional-dose therapy, dose escalation is associated with a high procedure-related mortality and a low response rate. In those patients who still have chemotherapy-responsive disease the response rate is high and mortality is low.(ABSTRACT TRUNCATED AT 250 WORDS)