Cerebral radiation therapy and chemotherapies can trigger central nervous system complications. For some products and protocols, neurological toxicity is a dose-limiting parameter. Clinical characteristics including acute encephalopathy, epilepsy, posterior reversible encephalopathy, progressive multifocal leukoencephalopathy, and vascular events are well described. Numerous products are involved in these complications and most have a specific toxicity profile. As more and more complex regimens are used, including several cytotoxic drugs and innovative targeted therapies, new toxicity profiles are emerging. The determination of the drug precisely involved in the patients' symptoms is getting more difficult. A good knowing of these complications and the implicated agents helps managing oncologic and reanimation care. Oncological prognostic has to be considered in the therapeutic discussion.