Facial expressions cause contraction of facial muscles which results in "dynamic" lines or wrinkles. Over time, these "dynamic" lines can become "static" (noticeable without any movement) and can deepen. Botox is a safe and effective treatment for dynamic wrinkles of the forehead, the glabellar frown lines (between the eyebrows), and the crow's feet. Use of Botox can both ameliorate present wrinkles and reduce the deepening effect of muscle contractions on wrinkles. Botox is a purified protein known as botulinum toxin type A, one of several toxins naturally produced by the bacteria, Clostridium botulinum. Small injections into muscles of facial expression cause a temporary reduction in the ability of a muscle to contract and therefore results in an improvement of facial wrinkles. This effect can last four to five months in most patients.