Botulinum toxin-physiology and applications in head and neck disorders.

This article is structured around a literature review that was carried out using Ovid and Medline with the key words "botulinum," "toxin," and "ENT." Botulinum toxin has been used safely in humans for more than 20 years. The effects are transient, such that treatments are required to be repeated at intervals. Its application to ENT provides a useful tool to treat dystonia, autonomic dysfunction, facial nerve paresis, and hyperfunctional lines. It may also be of benefit in laryngeal rebalancing and the treatment of headaches. Further research is being carried out and new indications for treatment with botulinum toxin may include sialorrhea and rhinorrhea.