Alternating non-cross-resistant chemotherapy has been induced for the treatment of non-Hodgkin's lymphoma (NHL) with the aim of cure, even in advanced cases. We formulated a new high dose regimen, CAMBO-VIP, which was a weekly treatment. They were administered during alternate weeks for a total period of 12 weeks. We obtained high response rate and prolonged disease-free survival with this regimen. We noticed the elevation of serum LDH level in some patients at or shortly after the completion of CAMBO-VIP treatment. LDH elevation was not associated with liver function abnormality in terms of elevation of GOT or total bilirubin. All of these patients were in complete or partial response with no evidence of tumor progression. An LDH isozyme study which was done at the time of LDH elevation showed elevation of both LDH1 and LDH2. Interestingly serum haptoglobin was undetectable in all 6 patients measured at the time of LDH elevation. Reticulocytosis and leukoerythroblastosis in peripheral blood were also observed in all of these patients. These abnormalities including LDH elevation returned to normal within a rather short period, usually within 1 to 3 weeks. From these observations, it is most likely that these abnormalities were due to excessive blood cell destruction, which was observed in association with rapid recovery from myelosuppression.