A rare, life-threatening form of poisoning in which a bacterial toxin in food damages the nervous system, causing paralysis

  • Eating home-preserved food is a risk factor
  • Age, gender, and genetics are not significant factors

The toxin that causes botulism is one of the most dangerous poisons known to humanity. This toxin is produced by the bacterium Clostridium botulinum, which can multiply rapidly in canned or preserved foods. If contaminated food is eaten, absorption of even minute amounts of toxin can cause severe damage to the nervous system.

Strict controls on commercial canning have made botulism caused by shop-bought products rare. The foods most commonly affected are home-preserved vegetables, fish, and fruit. Babies, who are especially susceptible to the effects of the toxin, may develop botulism after being given contaminated honey.

What are the symptoms?

The symptoms of botulism appear very suddenly, 12–36 hours after eating contaminated food. In the initial stages, the symptoms usually include:

  • Nausea and constipation.

  • Dry mouth.

Within 24 hours, these symptoms are followed by muscle weakness that starts in the eyes, causing blurred vision, and then progresses down the body. Without treatment, the respiratory muscles may become paralysed, causing suffocation.

What might be done?

Botulism needs immediate treatment in hospital with antitoxin drugs. For people whose breathing is affected, mechanical ventilation may be necessary. If given prompt treatment, 9 in 10 people make a full recovery.

To reduce the risk of poisoning, any bulging cans or abnormal-smelling preserved foods should be discarded, and home-preserved food should be cooked thoroughly. Babies under the age of 12 months should not be given honey.

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.

Back to top