The central neurotoxicity of cytotoxic drugs depends on their ability to cross the blood-brain barrier (BBB). The drugs with the highest neurotoxicity are therefore those that cross the BBB most easily: alkylating agents (metabolites of cyclophosphamide and ifosfamide, thiotepa and high-dose melphalan), busulfan, platinum derivatives, aracytine and methotrexate. Apart from aracytine-induced cerebellar toxicity, the clinical signs suggestive of chemotherapy neurotoxicity are relatively nonspecific: altered level of consciousness, seizures, behavioural disorders and motor deficits. Nevertheless, a good knowledge of the various neurological syndromes likely to occur can allow them to be attributed to a drug-induced cause. However, as patients may be receiving several potentially neurotoxic treatments (chemotherapy, concomitant drugs, neurosurgery, radiotherapy), it is difficult to formally confirm the responsibility of the drug, which should only be considered after confirming the absence of radiological and metabolic abnormalities. A specific antagonist treatment can be administered in rare cases (ifosfamide-induced encephalopathy).