The management of acute radiation syndrome in persons inadvertently exposed to total-body irradiation greatly benefits from the experience gained in previous clinical management situations. Within the framework of exposure to high doses, one of the most critical issues is the question of whether hematopoietic stem cell transplantation is indicated. A valid answer can be given with appropriate accuracy based on a thorough analysis and evaluation of all accessible case histories. Based on the clinical evaluation of patients severely affected with acute radiation syndrome, the following recommendations may be issued. There is limited indication for stem cell transplantation when there is accompanying severe radiation damage to organ systems other than the hematopoietic system. The optimum duration of pancytopenia can be estimated using the biomathematical model introduced in this article.