Near fatal subacute thallium poisoning necessitating prolonged mechanical ventilation. The authors describe a case of severe sensory-motor polyneuropathy caused by subacute thallium-intoxication rapidly progressing to respiratory failure due to complete muscle paralysis. After more than 2 months of mechanical ventilation, weaning from the ventilator was possible. Further intensive physical rehabilitation required an additional 6 months hospital stay, and 18 months later, neurological recovery was complete except for the distal lower limbs muscles. The authors discuss the different forms of thallotoxicosis and the present treatment is reviewed. Maximal prolonged therapeutic support should be offered in severe thallotoxicosis because of possible near complete recovery. 