[50] In January 2014, botulinum toxin was approved by UK's Medicines and Healthcare products Regulatory Agency for treatment of restricted ankle motion due to lower-limb spasticity associated with stroke in adults.

[51][52] In July 2016, the US Food and Drug Administration (FDA) approved abobotulinumtoxinA (Dysport) for injection for the treatment of lower-limb spasticity in pediatric patients two years of age and older.

[62] Commercial forms are marketed under the brand names Botox Cosmetic/Vistabel from Allergan, Dysport/Azzalure from Galderma and Ipsen, Xeomin/Bocouture from Merz, Jeuveau/Nuceiva from Evolus, manufactured by Daewoong in South Korea.

[66] Botulinum toxin is also used to treat disorders of hyperactive nerves including excessive sweating,[58] neuropathic pain,[69] and some allergy symptoms.

[99] Between 1817 and 1822, the German physician Justinus Kerner published the first complete description of the symptoms of botulism, based on extensive clinical observations and animal experiments.

He concluded that the toxin develops in bad sausages under anaerobic conditions, is a biological substance, acts on the nervous system, and is lethal even in small amounts.

[100] In 1870, the German physician Müller coined the term botulism to describe the disease caused by sausage poisoning, from the Latin word botulus, meaning 'sausage'.

[100] In 1895 Émile van Ermengem, a Belgian microbiologist, discovered what is now called Clostridium botulinum and confirmed that a toxin produced by the bacteria causes botulism.

[101] On 14 December 1895, there was a large outbreak of botulism in the Belgian village of Ellezelles that occurred at a funeral where people ate pickled and smoked ham; three of them died.

By examining the contaminated ham and performing autopsies on the people who died after eating it, van Ermengem isolated an anaerobic microorganism that he called Bacillus botulinus.

In 1910, the German microbiologist J. Leuchs published a paper showing that the outbreaks in Ellezelles and Darmstadt were caused by different strains of Bacillus botulinus and that the toxins were serologically distinct.

When the Army's Chemical Corps was disbanded, Schantz moved to the Food Research Institute in Wisconsin, where he manufactured toxin for experimental use and provided it to the academic community.

The mechanism of botulinum toxin action – blocking the release of the neurotransmitter acetylcholine from nerve endings – was elucidated in the mid-20th century,[105] and remains an important research topic.

Finally, inspired by Daniel B. Drachman's work with chicks at Johns Hopkins,[107] Alan B. Scott and colleagues injected botulinum toxin into monkey extraocular muscles.

After working out techniques for freeze-drying, buffering with albumin, and assuring sterility, potency, and safety, Scott applied to the FDA for investigational drug use, and began manufacturing botulinum type A neurotoxin in his San Francisco lab.

In 1986, Oculinum Inc, Scott's micromanufacturer and distributor of botulinum toxin, was unable to obtain product liability insurance, and could no longer supply the drug.

[112] The effect of botulinum toxin type-A on reducing and eliminating forehead wrinkles was first described and published by Richard Clark, MD, a plastic surgeon from Sacramento, California.

[113] Editors of the journal of the American Society of Plastic Surgeons have clearly stated "the first described use of the toxin in aesthetic circumstances was by Clark and Berris in 1989.

[117] This was initially thought to be an indirect effect of reduced muscle tension, but the toxin is now known to inhibit release of peripheral nociceptive neurotransmitters, suppressing the central pain processing systems responsible for migraine headache.

[118][119] As of 2018[update], botulinum toxin injections are the most common cosmetic operation, with 7.4 million procedures in the United States, according to the American Society of Plastic Surgeons.

These areas include the glabellar region between the eyebrows, horizontal lines on the forehead, crow's feet around the eyes, and even circular bands that form around the neck secondary to platysmal hyperactivity.

Evidence suggests that nerve exposure (simulated by injection of atropine and pralidoxime) will increase mortality by enhancing botulinum toxin's mechanism of toxicity.

[133] Commercial forms are marketed under the brand names Botox (onabotulinumtoxinA),[19][84][134] Dysport/Azzalure (abobotulinumtoxinA),[84][135] Letybo (letibotulinumtoxinA),[1][2][136] Myobloc (rimabotulinumtoxinB),[21][84] Xeomin/Bocouture (incobotulinumtoxinA),[137] and Jeuveau (prabotulinumtoxinA).

AbobotulinumtoxinA), a therapeutic formulation of the type A toxin manufactured by Galderma in the United Kingdom, is licensed for the treatment of focal dystonias and certain cosmetic uses in the US and other countries.

[142] Botulism toxins are produced by bacteria of the genus Clostridium, namely C. botulinum, C. butyricum, C. baratii and C. argentinense,[143] which are widely distributed, including in soil and dust.

For a period of four months, American blepharospasm patients had to arrange to have their injections performed by participating doctors at Canadian eye centers until the liability issues could be resolved.

[57][155] The effect of botulinum toxin type-A on reducing and eliminating forehead wrinkles was first described and published by Richard Clark, MD, a plastic surgeon from Sacramento, California.

Muscles affected by UMNS frequently are limited by weakness, loss of reciprocal inhibition, decreased movement control, and hypertonicity (including spasticity).

In January 2014, Botulinum toxin was approved by UK's Medicines and Healthcare products Regulatory Agency (MHRA) for the treatment of ankle disability due to lower limb spasticity associated with stroke in adults.

[175] Another hypothesis involves a connection between the facial muscle and specific brain regions in animals, but additional evidence is required to support or disprove this theory.