The risk, innovative treatment, clinical futures and prevention of the acute and chronic intoxications with pesticides are not clear at this time. The aim of the study was to research, to follow up and to detect the toxic efects of the pesticides in 78-year- old male patient with acute oral intoxication with phos – organic substance, that he have drunk by mistake. Materials and methodology: The patient was admitted from emergency department of the University Hospital – Pleven in toxicology department. He was in severe condition, with clinical findings for pulmonary, lever and renal failure. The patient was tested in the beginning: exact internal clinical examination, neurological examination, biochemistry tests, CT of the brain, reanimation procedures and treatment by anesthesiologist and neurologist. After the inicial improovement of the somatic and neurological condition and of the laboratory tests he developed coma. He was diagnosed with brain stem infarction in the left part of the mesencephalon at the nine day of the disease. At twelve day the patient dies. An autopsy study was provided. It completely confirms the clinical diagnose. Rezults and analyze: The analyze of the received results reveals, that for elderly patients even small doses from the toxic agent can produce severe and lethal health damages. The process of the patient’s education possess conventional, own important place in the prevention of the acute and chronic intoxications. The treatment is difficult, because the levels of AchE inhibitors can produce blocking of the transmition through the ion channels, direct effects on the receptor sites or by acting as agonists at the channel complex.