50 cases of advanced, intermediate (18) and high grade (32) non-Hodgkin's lymphoma (NHL) including 16 with Burkitt lymphoma have been treated with very high dose chemotherapy and autologous bone marrow transplantation (ABMT). These cases represent a retrospective analysis of the combined experience of a recently established collaborative group. 31 patients were treated with a protocol used in Lyon, 12 with that used in Marseille and seven with that used in London. Although the details of drug administration differed, each protocol was based on high dose alkylating agent (cyclophosphamide or melphalan), BCNU and cytosine arabinoside. 16 patients had drug resistant progressive NHL. Of these 11 responded to high dose treatment (nine CR, two PR). The duration of CR in this group was short (median 104d) and only one patient was in CR at 1 year. 19 patients had relapsed on previous therapy but were still responding to conventional rescue therapy. Following high dose therapy 47% of these patients are in continuous CR with a median time of observation of 300 d (73-962 d). Seven patients were partial responders to conventional induction therapy. Of these, six had a CR with high dose treatment and are still in CR (range 39-1230 d, median 200 d). Eight patients received high dose therapy as intensification after a long delay to CR with conventional treatment. Of these, four are alive and in remission 124-763 d after treatment. The high dose protocols produced significant morbidity with 25 patients (50%) having major or minor treatment-related complications, and there were seven treatment related deaths (14%). However, these results indicate that durable responses can be obtained with high dose chemotherapy in patients who have been heavily treated and indicate a role for this type of treatment at an earlier stage in advanced non-Hodgkin's lymphoma.