Botulinum toxin is a potent neurotoxin that blocks neuromuscular transmission. When injected in minute quantities it causes selective paralysis and weakening of muscle and is able to alleviate spasms. Because of this it is already an accepted treatment for blepharospasm and strabismus. However, it also appears to offer a useful therapeutic alternative for patients with various refractory pain syndromes, according to researchers at the 17th Annual Scientific Meeting of the American Pain Society [San Diego, US; November 1998].