It may surprise some people to learn that the often-lethal toxins produced by the Clostridium botulinum bacteria, which cause botulism illnesses, are a chief ingredient in certain cosmetic/medical products.  In fact, the FDA recently updated its safety warnings about medical products that contain botulism toxins.  The FDA advisory concerns four drugs specifically: Botox, Botox Cosmetic, Myobloc, and Dysport.  The safety warning states, in part, as follows: 

The boxed warning cautions that the effects of the botulinum toxin may spread from the area of injection to other areas of the body, causing symptoms similar to those of botulism. Those symptoms include potentially life-threatening swallowing and breathing difficulties and even death.

These symptoms have mostly been reported in children with cerebral palsy being treated with botulinum toxin for muscle spasticity, a use of the drugs that has not been approved by FDA. Symptoms have also been reported in adults treated both for approved and unapproved uses.


No definitive serious adverse event reports of distant spread of toxin effect have been associated with dermatologic use of Botox/Botox Cosmetic at the recommended doses (for frown lines between the eyebrows or severe underarm sweating). As well, no definitive serious adverse event reports of distant spread of toxin effect have been associated with Botox when used at approved doses for eyelid twitches or for crossed eyes.

A few words about botulism:

Botulism is a rare but serious paralytic illness caused by a nerve toxin that is produced by the bacterium Clostridium botulinum.  (see  Clostridium botulinum is the name of a group of bacteria commonly found in soil. It is an anaerobic, gram-positive, spore-forming rod that produces a potent neurotoxin. These rod-shaped organisms are intolerant of oxygen. The bacteria form spores, which allow them to survive in a dormant state until exposed to conditions that can support their growth. The organism and its spores are widely distributed in nature. They occur in both cultivated and forest soils, bottom sediments of streams, lakes, and coastal waters, in the intestinal tracts of fish and mammals, and in the gills and viscera of crabs and other shellfish.

Four types of botulism are recognized: foodborne, infant, wound, and a form of botulism whose classification is as yet undetermined. Foodborne botulism is the name of the disease (actually a foodborne intoxication) caused by the consumption of foods containing the neurotoxin produced by C. botulinum.

Foodborne botulism (as distinct from wound botulism and infant botulism) is a severe type of food poisoning caused by the ingestion of foods containing the potent neurotoxin formed during growth of the organism. The toxin is heat labile and can be destroyed if heated at 80°C for 10 minutes or longer. The incidence of the disease is low, but the disease is of considerable concern because of its high mortality rate if not treated immediately and properly. Most of the 10 to 30 outbreaks that are reported annually in the United States are associated with inadequately processed, home-canned foods, but occasionally commercially produced foods have been involved in outbreaks. Sausages, meat products, canned vegetables and seafood products have been the most frequent vehicles for human botulism.

How are botulism toxins used medically?

Clostridium botulinum bacteria produce seven different varieties of toxins, A through G.  Botulism toxins are the most acutely toxic substance known; a single teaspoon of the stuff is potent enough to kill about one-sixth of the world’s population.  The toxins work by attaching themselves at neuromuscular junctions–i.e. the nerve endings of muscles.  There the toxins disrupt nerve impulses, thereby causing what’s called flaccid (sagging) paralysis of the affected muscles.

There are surprisingly many ways that this devastating, often lethal neurotoxin, is used in medicine.  Aside from the common uses of Botox, botulism toxins have been used medically to treat excessive muscle contractions or twitching following a brain or spinal cord injury or in the context of cerebral palsy; strabismus (crossed eyes); as well as diseases of excessive sweating or drooling by reducing glandular secretions.   And these are just a few.  

But at what cost, or risk, are these lethal neurotoxins used for medical benefit?  The administration of a potent neurotoxin cannot be without its risks, and there are certainly plausible routes–e.g. the circulating bloodstream–by which the toxins could invade "more important" muscles and organs, like the heart or lungs.  Although the FDA qualifies its warning by stating "No definitive serious adverse event reports of distant spread of toxin effect have been associated with dermatologic use of Botox/Botox Cosmetic at the recommended doses," I suppose these kinds of potentially lethal complications are the "adverse events" being spoken of.