Sometimes, people can be exposed to moderateor high doses of radiation accidentally or through the environment. Radiation can cause great harm to several systemswithin organisms, especially the hematopoietic system. Severaltypes of drugs protect the hematopoietic system againstradiation damage in diff erent ways. They can be classifi edas “synthetic drugs” and “natural compounds.” Their cellularmechanisms to protect organisms from radiation damageinclude free radical-scavenging, anti-oxidation, reducinggenotoxicity and apoptosis, and alleviating suppression ofthe bone marrow. These topics have been reviewed to providenew ideas for the development and research of drugsalleviating radiation-induced damage to the hematopoieticsystem.