A case of Creutzfeldt-Jakob disease (CJD) in a 76 year-old man is presented. The clinical picture included a rapid progressive dementia associated with ataxia, global afasia, myoclonus and pyramidal signs; death occurred after about 4 months. There was an antecedent of chemical trauma caused by plant liquid on right eye 12 to 18 months before. The electroencephalogram showed diffuse slow activity and the neuropathological findings were typical. The detection of a protein called "prion" or PrP27-30 in the scrapie and the finding that some proteins isolated from brain of patients with CJD have reacted with antibodies raised against it have improved the knowledge about the infectious agent. The recent reports of young patients with CJD after human growth hormone therapy prepared from pools of pituitary glands obtained at autopsy are alarming and probably new cases will be described.