&NA;OPC 14117 is a novel cerebroprotective agent with CNS-stimulating activity. It is thought to act by inhibiting lipid peroxidation and has displayed neuroprotective effects against cerebral ischaemia in mice and rats. OPC 14117 is undergoing phase II clinical trials in the USA with Otsuka as a potential treatment for CNS trauma and cerebral ischaemia. In addition, a phase I/II trial in patients with HIV dementia has been conducted in the USA in collaboration with the Dana Consortium on Therapy for HIV Dementia and Related Cognitive Disorders. Otsuka also appears to be investigating the drug in phase II clinical trials in the USA and Japan for the treatment of Parkinson's disease and Huntington's disease.