A man inadvertently ate a whole root of the highly poisonous water hemlock (Cicuta virosa L.) plant. The chief symptoms were convulsions, unconsciousness, reddish tinted cyanosis, dilated pupils and marked metabolic acidosis. The patient survived due to treatment with haemodialysis, haemoperfusion, forced diuresis and artificial ventilation. The cicutoxin molecule size was calculated and it was found to be dialysable.