Botox has been used in the United States since 1990 and is derived from botulinum toxin Type A. Botulinum toxin toxin Type B was intruduced in 2001 and is called Myobloc.

Botox is best known as a controversial alternative to plastic surgery. It is used to treat wrinkes around the eyes and mouth. It is also used to treat dystonia, a neurological disorder which causes muscle spasming. The Botox stops nerve impulses from reaching nerve endings in the location where it is injected. It stops spasming in dystonia patients and those using it for cosmetic reasons use it because it paralyzes muscles, thus making their skin look smoother.

Botox injections can take 5-10 days to kick in, and may only last anywhere from a few weeks to a month once new nerve endings start growing back. It is one of the only treatments prescribed for dystonia, which affects 300,000 people in North America alone. Botulinum toxin is currently approved to treat spasms in the United States and Canada.

The site of the Botox injections to treat spasming are often determined by performing an electromyogram. The EMG is in a needle and will locate the places where muscle contractions are the worst. When Botox is injected into that area, it will have the best result.