Botox® is a trade name for botulinum toxin A. In this way, Botox® is related to botulism. Botulism is a form of food poisoning that occurs when someone eats something containing a neurotoxin produced by the bacterium Clostridium botulinum. Botulinum toxin A is one of the neurotoxins produced by Clostridium botulinum.
The most serious symptom of botulism is paralysis, which in some cases has proven to be fatal. The botulinum toxins (there are seven -- types are A through G) attach themselves to nerve endings. Once this happens, acetylcholine, the neurotransmitter responsible for triggering muscle contractions, cannot be released. A series of proteins, VAMP, syntaxin and SNAP-25, are essential for the release of acetylcholine. Certain botulinum toxins attack these proteins. Botulinum toxin A (Botox) affects the SNAP-25.
Basically, the botulinum toxins block the signals that would normally tell your muscles to contract. Say, for example, it attacks the muscles in your chest -- this could have a profound impact on your breathing. When people die from botulism, this is often the cause -- the respiratory muscles are paralyzed so it's impossible to breathe.
At this point, you may be wondering why anyone would want to have a botulinum toxin injected into his or her body. The answer is simple: If an area of the body can't move, it can't wrinkle.