Provided herein are therapeutic methods, kits, and pharmaceutical compositions for protecting a subject from radiation using a therapeutic agent selected from the group consisting of RRx-001 and a pharmaceutically acceptable salt thereof. One exemplary therapeutic method involves administering RRx-001 to the subject prior to the subject being exposed to the radiation, in order to protect the subject against radiation, such as ionizing radiation containing a-rays, ß- rays, ?-rays, neutron radiation, or a combination thereof.
