Early hematotoxicity following 4 to 8 courses of polychemotherapy has been analysed in 78 patients (mean age 32.5 years) treated for advanced stage Hodgkin's disease (53 stages III, 25 stages IV). Toxicity occurred in a third of the patients, and led to interrupt the treatment in one case out of 7, definitively in half of them. The thrombocyte lineage appeared the most sensitive to irradiation. Toxicity was proportional to the target volume (42% of upper and infra-diaphragmatic field versus 11.5% of one sided irradiation, P = 0.01). Toxicity was more frequent after infra-diaphragmatic irradiation (32% of para-aortic field, 43.75% of inversed Y field) than after mantle field (12.3%, P = 0.01). Tolerance to extended field irradiations seemed better in young patients. Sex, stage, type of chemotherapy did not influence toxicity in our series. Abnormalities of the blood count before irradiation was predictive of toxicity. While expecting development of megakaryocytic growth factors of autologous bone marrow transplantation, we suggest: 1) to achieve total lymphoïd irradiation in three periods (mantle field then lombo-aortic field-/+ spleen, then iliac and inguinal fields); 2) to wait, if possible, until normalization of the hemogram before starting the irradiation.