What is botulism?

Botulism is a serious illness that affects the nervous system. It occurs when poisonous substances called botulinum toxins produce skeletal muscle paralysis. This paralysis can affect the muscles that help you move and breathe.

Botulism is rare. But because it can cause death, it is important for people with symptoms of botulism to see a doctor right away.

What are the types of botulism?

There are several different kinds of botulism. Three kinds of botulism are the most common:

Foodborne botulism

Foodborne botulism happens when people eat contaminated foods that already contain the toxin.

Incorrectly processed food may allow the bacteria to grow which then releases the toxin into the food. Home-canned or improperly canned store-bought foods are common sources of foodborne botulism. Other food sources associated with this illness include:

  • Oils infused with herbs
  • Potatoes baked in aluminum foil
  • Cheese sauces
  • Bottled garlic
  • Foods kept warm or left unrefrigerated for too long

Infant botulism

Infant botulism typically occurs when babies ingest bacterial spores which are commonly found in soil or are fed foods which contain the spores, the most common being honey. The spores then become bacteria, which grow inside the baby’s intestines and release toxin.

Older children and adults have natural defenses against colonization, but infants younger than 12 months old don’t have those defenses. For this reason, experts advise that babies shouldn’t eat honey until they are at least 1 year old.

Wound botulism

Wound botulism develops when clostridium bacteria gets into a wound and grows. This type of botulism most often occurs in people who use a needle to inject drugs into their veins. In rare cases, it can also develop after surgery or a serious injury.

How common is botulism?

Few cases of botulism are reported in the United States each year. In 2016, 205 confirmed botulism cases were reported to the Centers for Disease Control.

Symptoms and Causes

What causes botulism?

Certain bacteria, including clostridium botulinum and clostridium butyricum, produce botulinum toxins. The spores of these bacteria are commonly found in soil but only rarely make people sick.

Specific conditions can cause bacterial spores to germinate and grow. These mature bacteria then secrete the toxin. When the toxin is released, it quickly spreads into the bloodstream and attaches to nerves. Botulism develops when those nerves no longer work. Conditions that allow spores to germinate include:

  • Lack of oxygen
  • Low acidity, sugar or salt
  • Cooking temperatures that are too low (even boiling may not destroy the spores)
  • Storage temperatures that are too warm

What are the symptoms of botulism?

Symptoms of botulism usually begin in the muscles of the face, eyes and throat. Without treatment, symptoms can spread to other parts of the body. Signs can appear from a few hours to several days after ingesting botulism spores. Symptoms include:

  • Drooping eyelids
  • Double or blurred vision
  • Slurred speech
  • Dry mouth
  • Trouble swallowing
  • Difficulty breathing
  • Weakness of paralysis of arms or legs

Diagnosis and Tests

How is botulism diagnosed?

To diagnose botulism, doctors do a physical exam. They check for weak or paralyzed muscles. Similar symptoms occur in other conditions including stroke and Guillain-Barre syndrome. Doctors may need to do further testing to make sure it is botulism.

To confirm the diagnosis, your doctor can conduct a test that shows the toxin is present in your blood, stool or vomit. Suspected food samples can also be tested for the toxin. Other tests include nerve conduction studies (EMG). Because the results of these tests can take several days, doctors often begin treatment right away before the test results are back.

Management and Treatment

How is botulism treated?

Doctors use a variety of treatments to remove botulism toxins from the body. In the most common treatment, a doctor provides a medication called antitoxin. This medication contains antibodies which attach and neutralize the toxin which stops the toxin’s effects in the body.

People with wound botulism may need an operation where doctors surgically remove the contaminated part of the wound. After this operation, people take antibiotics to keep the infection from coming back.

Some people may need treatments to manage the symptoms of botulism. They sometimes need to use a ventilator (machine that helps breathing) until any paralysis affecting their breathing goes away.

What are the complications or side effects of botulism?

Botulism can paralyze the muscles that help you swallow and breathe. It can cause breathing problems that could lead to death. It can also leading to choking that leads to aspiration of food or your mouth’s secretions.

What can people expect after treatment for botulism?

Depending on the severity of the case, recovery from botulism can take weeks, months, or even years. Most people who receive prompt treatment recover completely in less than 2 weeks.

Some people feel tired and short of breath for years after surviving botulism. Breathing exercises and other therapies can help them manage these symptoms. People with ongoing breathing problems may have to continue using a ventilator for weeks or even months.


Can botulism be prevented?

Yes, you can take steps to help prevent the most common types of botulism.

Foodborne botulism:

  • Refrigerate foods within 2 hours after cooking. Proper refrigeration prevents the bacteria from producing spores.
  • Cook food thoroughly.
  • Avoid food containers that appear damaged or bulging. (These can be signs of gas produced by the bacteria.)

Infant botulism: Do not give honey to babies under 1 year old.

Wound botulism:

  • Do not abuse injectable drugs.
  • Seek medical treatment for a wound with signs of infection including redness, tenderness, swelling or pus
  • Clean wounds contaminated by dirt and soil thoroughly.

Outlook / Prognosis

What is the outlook for people with botulism?

Botulism can be fatal if left untreated. But most people who receive a prompt diagnosis and treatment can make a full recovery from the illness. They return to normal function throughout their lives.

Last reviewed by a Cleveland Clinic medical professional on 05/14/2018.


  • Centers for Disease Control and Prevention. Botulism. ( Accessed 5/14/18.
  • World Health Organization. Botulism Fact Sheet. ( Accessed 5/14/18.
  • Botulism. ( Accessed 5/14/18.
  • U.S. National Library of Medicine. Botulism. ( Accessed 5/14/18.
  • Centers for Disease Control and Prevention. National Botulism Surveillance. ( Accessed 5/14/18.

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