Trademark name for botulinum toxin, used for cosmetic treatment of wrinkles.

Botox is most famous for its use in temporarily reducing wrinkles. It was originally developed as a treatment for crossed eyes, facial spasms and other neurological disorders characterized by abnormal muscle contractions.

Botox is a purified form of Botulinum Toxin Type A, a toxin produced by the bacterium Clostridium botulinum. This bacterium causes severe food poisoning and even death when ingested. It also causes muscles in the face to "relax”. The discovery of this property of the toxin led to its medical and cosmetic applications. The toxin is extremely deadly if eaten, but appears to show few ill effects when injected in very small doses.

Side effects of Botox injections can include temporary weakness of the muscles around the eye. As a result, patients may have trouble lifting their eyelids or may experience double vision. Patients can also have pain and bruising around the injection site. Errors in the amount or location of the injection can occur, causing drooping lids and, if used in the neck, muscle weakness and difficulty swallowing. With an experienced physician, these side effects are considered rare. Botox treatments are temporary and need to be repeated every 3 to 6 months.