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Botulism is a rare but potentially fatal infection caused by toxins (poisons) that are produced by bacteria called clostridium botulinum.

The toxins produced by clostridium botulinum are the most powerful naturally occurring toxins known to science. They attack the nervous system (the nerves, brain and spinal cord) and cause paralysis (weakness). Left untreated, the paralysis will spread to the lungs, causing breathing failure followed by death.

There are three different ways of contracting botulism. They can be classified as:

  • food-borne botulism
  • wound botulism
  • infant botulism

These are described in more detail below.

Food-borne botulism

Food-borne botulism is caused by eating food that has been contaminated with the botulinum toxin as a result of it being improperly canned or preserved.

Wound botulism

Wound botulism occurs when a wound becomes infected with botulism spores, which then produce toxins. This usually occurs when the tissue is damaged through the injection of contaminated heroin or the snorting of contaminated cocaine.

Infant botulism

Infant botulism can occur if a baby swallows some botulinum bacteria spores, which produce toxins in their intestines (part of the digestive system).

Infant botulism usually only affects babies who are less than 12 months old. After a year, children develop a defence against the spores.

How common is botulism?

Botulism is relatively rare in the UK. There have only been 33 recorded cases of food-borne botulism in England and Wales since 1989. Twenty-seven of these were linked to a single outbreak that was caused by contaminated hazelnut yoghurt. Since 1978, there have been eight cases of infant botulism. None of these cases resulted in death.

In contrast to food-borne botulism and infant botulism, the number of wound botulism cases has risen sharply since 2002. In 2006, there were 22 recorded cases, which resulted in two deaths. There were a further 11 cases in 2007. The rise in wound botulism is thought to be due to people injecting heroin directly into their muscles, a practice that is often referred to as 'skin-popping'.


If treated promptly, the outlook for someone with botulism is usually good. Antitoxins have proven to be very effective in successfully treating the condition, although a full recovery may take several months. In 1 or 2 cases out of 20, botulism can be fatal.

Botulism is not contagious and cannot be spread through person-to-person contact. It also cannot enter the body through intact (unbroken) skin.

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Botulism is a serious medical condition that requires immediate medical attention. Dial 999 to request an ambulance if you suspect that you, or someone you know, is having symptoms of botulism.

Food-borne botulism

The symptoms of food-borne botulism usually begin with:

  • nausea (feeling sick)
  • vomiting
  • diarrhoea, followed by constipation (being unable to empty your bowels)

It usually takes 12 to 36 hours after eating the contaminated food for the more serious neurological symptoms (symptoms that affect the nervous system) to begin (see below). However, it can sometimes take as little as six hours, or as long as eight days.

If you have eaten (or drunk) a large amount of the toxin that is produced by the clostridium botulinum bacteria, you may not have these early symptoms. Instead, you may develop the neurological symptoms straight away. 

Wound botulism

Following the initial infection, the symptoms of wound botulism take between 4 to 14 days to develop. The symptoms start in the cranial nerves (nerves that connect your brain to your spine) before spreading through your body as the toxins take effect.

Neurological symptoms 

The neurological symptoms (symptoms that affect the nervous system) of food-borne botulism and wound botulism are the same. However, in cases of wound botulism, the symptoms can take longer to develop. The neurological symptoms include:

  • double vision
  • droopy eyelids
  • facial weakness
  • dry mouth
  • difficulties swallowing (dysphagia)
  • slurred speech

As the toxin spreads, you will have weakness and paralysis in your upper limbs. If the toxin is allowed to keep spreading, your breathing will be affected and you will eventually have respiratory failure, resulting in death.

Your sensory awareness (your awareness of the world around you) will be unaffected. There are also no symptoms of fever, such as a high temperature, during a botulism infection.

Infant botulism

The symptoms of infant botulism usually begin with constipation (difficulty passing faeces). This may last for several days before the infant begins to have neurological symptoms, such as:

  • an inability to suck
  • a floppy head
  • floppy muscles
  • weak crying
  • tiredness
  • irritability
  • poor reflexes
  • heavy eyelids and flat, unfocused eyes
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Botulism is caused by the bacteria clostridium botulinum, which is found in:

  • soil
  • dust
  • agricultural products, such as honey, beans and corn

The bacteria themselves are not harmful but, if they enter your body, they can begin to produce highly poisonous toxins.

Clostridium botulinum

The clostridium botulinum toxin is the deadliest naturally occurring poison in the world. Just 500g (1.1lb) is enough to kill every human being on the planet.

Clostridium botulinum can produce seven different types of toxin, which are classified as types A through to G. Types A, B, E and F are poisonous to humans. Type F is the most toxic. It is 60 times more poisonous than type B, which is the least toxic.

The toxins produced by clostridium botulinum block a special type of chemical called a neurotransmitter. Neurotransmitters send messages from your brain to the rest of your nervous system (your nerves and spinal cord).

In the case of botulism, the toxin blocks the effects of a neurotransmitter called acetylcholine, which is used by your body to help stimulate muscles. If acetylcholine is blocked, it causes paralysis which, if left untreated, can lead to death.

Food-borne botulism

Food-borne botulism can occur when food becomes contaminated with infected soil. If the food is not properly canned, preserved or cooked, bacteria in the food can start to produce toxins, which are highly poisonous if eaten.

Modern food production techniques use high-temperature processes that ensure that all bacteria are killed. Therefore, cases of food botulism are virtually unheard of in the UK.

Since an outbreak of food-borne botulism in 1989, where contaminated hazelnut yoghurt affected 27 people, there have been another six cases of food-born botulism in the UK up to 2006. All of these were caused by eating homemade food that was prepared in other countries.

Wound botulism

Wound botulism occurs when a wound becomes infected with the clostridium botulinum bacteria. This is caused by injecting or sniffing drugs that are contaminated with the bacteria. Once inside your body, the bacteria produce the poisonous toxins.

In England and Wales, wound botulism used to be very rare with no recorded cases before the year 2000.

But from 2000 to 2007, there were 130 cases of wound botulism in England and Wales. All of these occurred in people who were injecting heroin into their muscles. Most heroin users inject the drug into their veins (intravenously), but some users prefer to inject into the muscles. This may be because:

  • they are trying to disguise the signs of heroin injection ('track marks'), or
  • their veins have been damaged by previous heroin abuse

Injecting heroin directly into the muscles is very dangerous because it causes tissue damage, which can lead to infection.

It should be stressed that using clean needles or avoiding sharing needles will not prevent wound botulism because it is not the needle that is infected, but the heroin itself.

Most heroin in the UK comes from opium poppies that are grown in Asia or the Middle East, particularly Afghanistan. The opium is cooked, and the morphine is extracted before being treated with chemicals to produce heroin. The drugs are then often 'cut' with bulking materials, such as starch and lactose. The heroin can become contaminated at any point during this process.

Some cases of wound botulism have also been linked to nasal tissue damage caused by snorting cocaine. The damaged tissue can then become infected. However, no cases of this kind have ever been recorded in the UK.

Infant botulism

Infant botulism occurs when a baby ingests spores of the clostridium botulinum bacteria. The spores make their way to the intestine (part of the digestive system) where they begin to produce toxins.

Clostridium botulinum bacteria spores are harmless to older children and adults. This is because after about one year of age you develop defences that counter the effects of the spores.

Honey and corn syrup have been known to cause some cases of infant botulism, although no definitive cause was found in the majority of cases. There have been eight cases of infant botulism in England and Wales between 1978 and 2007.

Alternative causes

It is possible to be infected with the botulinum toxin in other ways, although these have never happened in the UK. Possibilities include:

  • an incorrect injection during botox – this is a beauty treatment that uses the toxin to temporarily paralyse the facial muscles in order to reduce wrinkles
  • inhaling (breathing in) the toxin when it is in the form of a gas – this would need to be deliberately prepared, for example, by terrorists
  • drinking the toxins in water – the normal treatment of water in the mains water supply would deactivate the toxins, so this would need to be contaminated deliberately, for example, by terrorists
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If you think that you or someone you know have botulism, dial 999 immediately to request an ambulance.

Once you are in hospital, the doctors treating you may suspect botulism if you have the following three symptoms:

  • a number of different paralyses, including double vision, difficulty swallowing and slurred speech
  • you do not have a fever (high temperature)
  • your sensory awareness (your awareness of the world around you) is not affected


As botulism is such a rare condition, a number of tests are usually carried out to rule out other conditions with similar symptoms, such as:

Tests that you may have include:

  • a magnetic resonance imaging (MRI) scan – strong magnetic field and radio waves are used to produce detailed images of the inside of your body
  • a computerised tomography (CT) scan– a series of X-rays of your body are taken at slightly different angles, and a computer puts the images together
  • a lumbar puncture (spinal tap) - a hollow needle is inserted into your lower back to extract a sample of cerebrospinal fluid (fluid that surrounds and protects your spine)


In order to confirm the diagnosis, tests will be carried out to detect the clostridium botulinum bacteria or the botulinum toxin produced by the bacteria. Depending on which type of botulism you have, this may be found in a sample of:

  • your blood
  • your faeces (stools)
  • the contents of your stomach (for food-borne botulism)
  • pus or tissue from a wound (for wound botulism)
  • the contaminated food, if you still have some left (for food-borne botulism)  
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Treatment for botulism will depend on which type of botulism you have, although in all cases you will need to be admitted to hospital. If botulism is not treated quickly, it is likely to be fatal. 

It can take 10 days to several months for someone to fully recover from the botulinum toxin.

Food-borne and wound botulism

Treatment for food-borne and wound botulism will require immediate admission to hospital. If you are having difficulty breathing because the toxin has spread to your lungs, you may be attached to a ventilator (an artificial breathing machine that moves oxygen-enriched air in and out of your lungs).

You may also be given fluids and nutrients through an intravenous drip (a tube is placed directly into a vein in your arm).


Botulism will need to be treated with injections of antitoxins. Antitoxins are antibodies (proteins produced by the body) that can neutralise a specific toxin, in this case the clostridium botulinum toxin.

The antitoxins are created by exposing horses to a form of botulism that they are immune to. This exposure produces antibodies, which are harvested and used to create an antitoxin. Antitoxins work by blocking the effects of the toxin on the nervous system (the nerves, brain and spinal cord).

Antitoxins should be given as soon as possible. It is not necessary to wait for test results confirming the presence of the clostridium botulinum bacteria or toxin. A diagnosis of botulism based on your symptoms is enough to start treatment.

A case of botulism will need to be reported to the Health Protection Agency (HPA) by the doctor who diagnoses you. The HPA will then provide the antitoxin.

The antitoxin will help prevent your symptoms from getting any worse, but it will not cure any paralysis that the toxin has already caused. If one dose of antitoxin is not enough, you may be given a second dose after 24 hours.

Food-borne botulism

In some cases of food-borne botulism, medicines may be used to induce vomiting (being sick) in order to remove all particles of infected food from your body. Enemas (an injection of fluid into the large intestine) may also be used for this purpose because they encourage you to empty your bowels.

Wound botulism

If the infection has been caused by wound botulism, the infected wound and possibly a surrounding area of skin will need to be surgically removed. The process for doing this is called debridement. Removing the area surrounding the wound is necessary in order to stop any further toxins being produced. In some cases, this may lead to scarring.

You may also be given antibiotics (medicines to treat an infection that is caused by bacteria) to prevent any further infections.

Infant botulism

Infant botulism tends to be less serious than other types of botulism. This is because the levels of toxins that are released by the bacteria are lower than in other forms of the condition. However, the condition still requires emergency medical treatment in order to prevent breathing difficulties occurring.

Babies with infant botulism will be placed in an incubator (a clear, enclosed cot) that will keep them warm and protect them from secondary infection. Artificial ventilation may be required to assist their breathing, and they may also be fed intravenously (though a tube placed directly into a vein).

Infant botulism can be successfully treated using a medicine known as botulinum immunoglobulin (which has the brand name BabyBIG). Botulinum immunoglobulin is created by taking samples of human blood that contain a high level of infant botulism-immune antibodies (proteins that fight infections).

Most babies will respond quickly to treatment, and they should be well enough to leave hospital within two-and-a-half weeks. Any paralysis may last for a few weeks, but babies grow new nerve endings, so they should make a full recovery.

Therapeutic uses of botulinum toxin

Miniscule amounts of botulinum toxin are used in several medical procedures. Beauty treatments are one of the best known applications of botulinum toxin. For example, injections of the toxin are sometimes used to remove the appearance of wrinkles by temporarily paralysing the facial muscles. This procedure is commonly known as 'botox'.

Botulinum toxin is also sometimes used to treat muscle disorders, excessive sweating and, more recently, migraines.

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There is a concern that botulism toxin could be deliberately released as an act of terrorism.

However, as the condition is very rare, a deliberate release of botulinum toxin should be easy to detect. Doctors have to report every suspected case of botulism to the Health Protection Agency (HPA).

In the event of a deliberate release of the botulinum toxin, the HPA would isolate the area of exposure and give antitoxins to anyone who is affected.

In the unlikely event that you suspect exposure to the aerosol form of the botulinum toxin (where particles of the toxin are suspended in gas), you should cover your nose and mouth with clothing, such as a shirt or scarf. The toxin cannot penetrate unbroken skin.

Then report immediately to the nearest healthcare professional for decontamination. However, if this is not possible, wash your skin and clothes with warm water, and use bleach to clean any surfaces or objects that may have been contaminated.

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Food-borne botulism

Due to the high standards of food hygiene in the UK, the chances of getting food-borne botulism from food brought in this country are virtually nil.

There is a slightly higher risk if you manufacture your own food, particularly if this involves canning. However, following standard food hygiene procedures and canning recommendations will reduce any risk.

Wound botulism

If you are a heroin user, avoid injecting heroin into your muscles. An intravenous injection (an injection into a vein) or smoking heroin is a safer way to take the drug.

However, the safest course of action is to stop using heroin altogether. Your GP will be able to refer you to your local community drug treatment team.

Methadone programmes are available to help people with heroin addictions to stop using heroin. Methadone is much safer than heroin because, unlike heroin, it does not contain any impurities, and it can be taken in liquid form. Ask your GP or drug counsellor for more information about methadone.

See the topic about Drug misuse for more information and advice about drug addiction and recovery.

Infant botulism

In the majority of cases of infant botulism, no specific cause has ever been identified. Therefore, it may not always be possible to prevent the condition occurring.

However, it is recommended that you should avoid giving honey or corn syrup to children who are under 12 months old because they have been known to contain bacterial spores.

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