A rare type of food poisoning with a greater than 50 per cent death rate, caused by the presence of the exotoxin of the anaerobic bacterium Clostridium botulinum, usually in contaminated tinned or bottled food. Symptoms develop a few hours after ingestion.

The toxin has two components, one having haemagglutinin (blood coagulating)activity and the other neurotoxic activity, which produces most of the symptoms. It has a lethal dose of as little as 1 mg/kg. The symptoms are dry mouth, constipation, urinary retention, dilated pupils with blurred vision, progressing to muscle weakness and eventual paralysis. Treatment consists of supportive measures such as artificial ventilation, 4 aminopyridine, and 3, 4 di-aminopyridine, which may antagonise the effect of the toxin.