Botulinum toxin (BTX) is a neurotoxic protein produced by the bacterium Clostridium botulinum and related species. It is also produced commercially for medical, cosmetic, and research use. There are two main commercial types: botulinum toxin type A and botulinum toxin type B.

Botulinum toxin is used for a number of medical problems. When injected in small amounts it can effectively weaken a muscle for a period of three to four months.

It is used in the treatment of spasms and dystonias.

The conditions approved for treatment with botulinum toxin include:

  • cervical dystonia (spasmodic torticollis), a neuromuscular disorder of the head and neck
  • blepharospasm, uncontrolled muscle contraction or twitch of the eyelid;
  • severe primary axillary hyperhidrosis, a condition of excessive sweating;
  • chronic migraine, defined by patient history, and high frequency of occurrence
  • strabismus, improper alignment of the eyes (heterotropia; “crossed eyes”)

In cosmetic applications, injection of botulinum toxin can be used to prevent development of wrinkles by relaxing facial muscles. Following treatment, visible results of Botox Cosmetic are usually seen within 3–5 days, however it can take up to 2 weeks to see full results.