Botox (short for Botulinum toxin type A) is a purified neurotoxin that temporarily relaxes muscles and is commonly used for both cosmetic and medical purposes. Botox is used cosmetically for reducing the appearance of wrinkles and lines and makes skin smoother and more youthful looking over the treated area, and medically to treat chronic migraines, excessive sweating (hyperhidrosis), and muscle spasms.