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Botulism

What You Need to Know

  • Botulism is a rare but serious disease caused by a toxin (poison) that attacks the nervous system and causes paralysis. Anyone can get botulism.

  • There are different forms of botulism, including foodborne botulism, wound botulism, and infant botulism. Botulism doesn't spread from person to person.

  • People with botulism usually have weakness or paralysis that starts in the head and face and spreads down to the rest of the body.

  • Without medical care, botulism can lead to death. If you or someone you know has symptoms of botulism, call 911 or go to the emergency room immediately.

  • You can help reduce your risk of botulism by properly storing and preserving food, and by not injecting street drugs (like black tar heroin). To help reduce the risk of botulism in babies, do not feed babies honey.

  • If you are a healthcare provider and suspect your patient (non-infant) may have botulism, please contact the local health department (LHD). If unable to reach the LHD, providers may contact the CDPH Duty Officer at (916) 328-3605.


What is botulism?

Botulism is a rare but serious disease caused by a toxin (poison) that is made by bacteria called Clostridium botulinum (C. botulinum). This botulinum toxin attacks the nervous system and causes paralysis.

A person who becomes sick with botulism may have:

      • Droopy eyelids
      • Double or blurry vision
      • Muscle weakness in the face
      • Trouble swallowing
      • Slurred speech or trouble speaking
      • Weakness in the arms and legs

A person with botulism might not have all of these symptoms at the same time. Botulism can also weaken the muscles that control breathing. Without medical care, botulism can lead to death.

Babies younger than 15 months old can get infant botulism and may appear tired, show little facial expression, have a weak cry or poor head control, and appear “floppy” because they can’t control their muscles. 

If you or someone you know has symptoms of botulism, call 911 or go to the emergency room immediately.

Botulism symptoms include trouble swallowing, droopy eyelids, blurry vision, slurred speech, weak muscles, and trouble breathing 

How can a person get botulism? 

Bacteria called Clostridium botulinum make spores, which are dormant (or inactive) cells resistant to extreme conditions (such as hot temperatures). C. botulinum spores are common in the environment, including in the soil and dust. Most of the time, C. botulinum spores do not make people sick.
But under certain conditions (especially in low-oxygen, low-acid, and low-sugar environments), the spores can grow and make the harmful botulinum toxin which causes paralysis.

A person can get botulism in different ways. The different types of botulism are determined by how a person is infected:

Botulism is not contagious, which means it cannot be spread from person to person.


  • Foodborne botulism is caused by eating or drinking something that is contaminated with the botulinum toxin.

    • Home-canned foodsFoods that aren’t properly processed, fermented, pickled, preserved, stored, or refrigerated can create the right environment for C. botulinum spores to grow and make the botulinum toxin. 


      Foods that can be risky for botulism are usually low in acid, salt, or sugar and may include: 

      • Home-canned or home-pickled foods, especially meat or vegetables that aren’t properly preserved

      • Fermented tofu in glass jarHome-fermented foods, including fermented fish and fermented tofu (also called chao or furu) that aren’t fermented properly

      • Perishable, store-bought foods that aren’t properly refrigerated (such as soups and chowders)


  • Wound botulism is caused by C. botulinum spores getting into a wound or opening in the skin and making the botulinum toxin.

    • People who inject street drugs like black tar heroin are more likely to get wound botulism than people who do not because C. botulinum spores can get in through the injection site and make the botulinum toxin.

    • Rarely, a traumatic injury (like an open fracture) where dirt or soil gets into the wound can cause wound botulism.


  • Infant botulism is caused by C. botulinum spores that get into an infant’s intestines and grow and make the botulinum toxin.

    • Honey can contain C. botulinum spores and should not be fed to babies younger than 12 months.

  • Adult intestinal toxemia (adult intestinal colonization) is similar to infant botulism and is caused by C. botulinum spores that get into an adult’s intestines and grow and make the toxin.

    • People with severe gut illnesses or past intestinal surgery are more at risk for this type of botulism, but it is very rare.

  • Iatrogenic botulism is caused by accidentally injecting too much botulinum toxin for cosmetic or medical reasons.

    • Botulinum toxin can sometimes be used for medical treatment or cosmetic reasons (like for wrinkle treatment or headaches). In rare cases, injections of too much botulinum toxin can cause symptoms of botulism. 

Although botulism is rare, all forms of botulism can cause death and are considered medical emergencies.

What can happen if someone has botulism?

If not treated quickly, paralysis from botulism starts in the head and face and usually moves down the body, causing breathing problems, full paralysis, and even death. About 1 in 20 people who get botulism die from respiratory failure or the result of long-term paralysis.

Symptoms of foodborne botulism usually begin about 18 to 36 hours after eating or drinking something that is contaminated with the botulinum toxin, but symptoms can occur as early as 6 hours or as late as 10 days.

People with wound botulism may not have symptoms until several days after the wound is infected or injecting contaminated drugs.

How is botulism treated?

Botulism is a very serious disease that can be deadly if not treated. If caught early, botulism can be treated with botulinum antitoxin, which blocks the toxin from causing more harm in the body. But the antitoxin can’t undo any muscle paralysis that has already happened, so it can take weeks or even months for a person to get better. A person with severe botulism may need help breathing and may need to be on a breathing machine (ventilator) for weeks with intensive medical care.

Botulinum antitoxin for patients 15 months of age and older in California is available by working with the local public health department, CDPH, and the U.S. Centers for Disease Control and Prevention (CDC). If the diagnosis of botulism is suspected, healthcare providers can ask for the botulinum antitoxin through their local health department, which will work with CDPH and CDC to release the antitoxin. For infant botulism, healthcare providers should contact the CDPH Infant Botulism Treatment and Prevention Program to obtain the licensed human botulinum antitoxin, BabyBIG. 

How can I reduce my risk of getting botulism?

Person looking at a jar of canned food

To help reduce your risk of foodborne botulism, it’s important to know that some kinds of food are more likely to cause botulism than others. Because C. botulinum spores are common in the environment and can contaminate food, careful steps must be taken to prevent toxin from growing in food.

  • Always carefully read and follow label instructions for proper handling or storage of food (ex: “Keep refrigerated”), including food that you buy from the store.

    • In general, keep hot foods hot (by heating or cooking) and cold foods cold (by refrigerating) — doing this helps prevent harmful bacteria from growing and making toxin in your food.

    • After you open any canned or pickled foods, store them in the refrigerator.

Keep Refrigerated     
  • Never eat food that is moldy, smells rotten, or smells different than it is supposed to smell — this can be a sign that the food is contaminated with germs that can make you sick. Remember: When in doubt, throw it out!
Moldy Food Jar    
  • If you preserve food at home by canning, fermenting, or pickling, be aware of the risk of foodborne botulism! To lower your risk of getting botulism, make sure your home-preserved food:

    • Is preserved with enough salt or sugar

    • Is preserved with enough acid (such as citric acid or vinegar)

    • Is kept refrigerated or frozen

Home canning supplies







Syringe with needle on the ground

To reduce your risk of wound botulism, do not inject street drugs. Learn more on the CDC Injection Drug Use and Wound Botulism webpage.

You can also help reduce the risk of wound botulism by keeping all wounds clean. If you start to see any signs of infection (like fever, redness, or pain around a wound), see a healthcare provider right away.



To help reduce the risk of infant botulism, do not feed honey to babies less than 12 months old. For information on infant botulism, visit the CDPH Infant Botulism Treatment and Prevention Program webpage.


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