Botox injections are the best known of a group of medications that use various forms of botulinum toxin to temporarily paralyze muscle activity. This toxin is produced by the microbe that causes botulism, a type of food poisoning.
Botox injections are noted primarily for the ability to reduce the appearance of some facial wrinkles. They are also used to treat such problems as repetitive neck spasms (cervical dystonia), excessive sweating (hyperhidrosis), overactive bladder and lazy eye. Botox injections may also help prevent chronic migraines in some people.
Botox was the first drug to use botulinum toxin. Other products now include Dysport, Myobloc and Xeomin. Each is a little different, particularly when it comes to dosage units, so they aren't interchangeable.
Mayo Clinic's approach