After suffering a carbon monoxide intoxication, a thirty-nine-year-old patient presented a marked behavioral change, with a severe anterograde and retrograde amnesia, extreme placidity, bulimia, and hypersexuality. This picture lasted for twenty days. Placidity and anterograde amnesia persisted, while marked psychic akinesia and abnormal involuntary movements soon appeared. A CT scan disclosed bilateral low density lesions involving the pallidum. The patient showed marked improvement after treatment with bromocriptine.