Although the toxic effects of acrylamide on the peripheral nervous system have been well established, less attention has been paid to its effects on the brain. Nevertheless, (1) ultrahigh field magnetic resonance imaging revealed enlarged cerebral ventricles and cisterns in rats treated with acrylamide 50 mg/kg/d for 8 d, (2) creatine kinase (CK) activities were suppressed in the brain from such rats and mice, (3) CK activities in the brains of mice intoxicated with acrylamide changed in parallel with neurological dysfunction, (4) in human cases of acrylamide intoxication due to occupational exposure, symptoms suggesting brain involvement were seen in a few, and (5) cases of acrylamide intoxication due to contaminated well water showed unquestionable signs of brain dysfunction including mental confusion with hallucinations. These indicate that acrylamide can cause encephalopathy in animals as well as in humans, and that the spectrum of impairment of the nervous system can vary greatly depending on the mode of exposure.