The present invention relates to the use of nanodiamonds as drugs generating free radicals, in particular for treating tumors. The invention is based on generating free radicals on the surface of the nanodiamonds when they are exposed to radiation, for example ionizing radiation. In order to increase the effectiveness of the nanodiamonds, the nanodiamonds can be complexed with a radiosensitizing agent, such as a chemical molecule or an interfering RNA targeting a repairing gene.
