We have studied fifty cases of thallium intoxication during the past nine years. Twenty-eight occurred in women and twenty-two in men. One of the patients was a new born whose mother had this type of intoxication during her third trimester of pregnancy. The ages varied from one day to 84 years and in all cases the source of thallium was ingestion of rat poison, except for the baby who received it across the placenta and an other patient whose source was transdermal. Twenty-three of the cases of intoxication were accidental, twenty-one were suicidal attempts and five were homicidal. One case did not know the source of intoxication. Thallium levels were measured in the urine of all the patients, some were measured in blood, as well as cerebrospinal fluid. The main clinical manifestation was a mixed type of severe peripheral neuropathy, with abdominal pain, nausea, vomiting and alopecia and some cases had psychiatric manifestations. Electrophysiological studies and nerve biopsy examined with electron microscopy in three patients. Magnetic nuclear resonance, computerized axial tomography of the abdomen and cranium were performed in two patients. There was only one death and the rest of the patients recovered almost completely. Pathophysiology and pharmacological management of this type of neurointoxication are revised.