Prolonged, low-level exposure to inorganic arsenic can produce peripheral neuropathy in humans, and is a serious industrial health hazard. The clinical expression of arsenic neuropathy is similar to other toxic neuropathies of the dying-back type. No satisfactory animal model of arsenic neuropathy has been devised. Rats underwent weekly intraperitoneal injections with solutions of arsenic trioxide. Strengths of 2mg/kg, 5mg/kg, 10mg/kg and 15mg/kg were used. The 15 mg/kg animals died shortly after receiving the injection. The other animals survived and, after eighteen months, appeared normal. Histopathological study of the peripheral and central nervous systems of these animals was unremarkable. It appears that the rat is not the appropriate species for the study of inorganic arsenic neurotoxicity.