Botulinum toxin is a neurotoxin that is produced by Clostridium botulinum. At one time, this toxin was only seen as a lethal substance, but now scientists have found many medical uses for it. There are eight distinctive toxins (A-H), but only A and B currently have clinical uses. Botulinum toxin A has three different versions that are U.S. Food and Drug Administration (FDA) approved: onabotulinumtoxinA (Botox®), abobotulinumtoxinA (Dysport®), incobotulinumtoxinA (Xeomin®). Botulinum toxin B is also FDA approved as rimabotulinumtoxinB (Myobloc®). The toxins work by inducing reversible, local, dose-dependent chemodenervation by inhibiting acetylcholine release from presynaptic terminals. These drugs are approved to treat many different types of disorders but have found significant use for the treatment of migraines, dystonias and cerebral palsy. Botulinum toxin has proven to be efficacious in prophylactically treating those patients with migraines who have failed other pharmacologic and nonpharmacologic treatments. Botulinum toxin is also FDA approved for the treatment of dystonias; more specifically, all three types of botulinum toxin A and the rimabotulinumtoxin B have FDA approval for the treatment of cervical dystonia. Perhaps the most important use for botulinum toxin is in patients with cerebral palsy. Botulinum toxin is efficacious in patients with upper limb spasticity who are not good surgical candidates. It also proves useful as an adjunct to physiotherapy in these patients. This can help reduce or slow progression in patients with cerebral palsy. Exercise has been shown to be an efficacious treatment in patients with migraines, dystonias and cerebral palsy. Further research is necessary to determine the potential benefits the combination of exercise and botulinum toxin can have in these patients. While the high cost of botulinum toxin might deter some patients, it is a good option for those that have exhausted other options or are not good candidates for surgery.