Botulinum toxin has been used in cosmetic surgery for more than 20 years and is being used more and more. This application is based on its mechanism of action on human tissues, combined with the requirements of human aesthetics to bring the effects of botulinum toxin into play gradually. So what is the target organ and the principle of action of botulinum toxin? (a), relaxation of skeletal muscle Botulinum toxin has specific affinity with motor nerve, can stay in the neuromuscular junction and bind with its surface receptors, and bind with enzyme complexes inside the nerve endings, splitting SNAP-25 protein, inhibiting the release of neurotransmitters and acetylcholine, thus blocking the transmission of nerve impulse signals and causing temporary denervation relaxation or paralysis of skeletal muscle. The effect of botulinum toxin is not permanent, the reason is that botulinum toxin is a protein that will be gradually metabolized and inactivated by the body, and secondly, the organism can produce newborn nerve endings synapses to restore the connection between nerves and muscles. (b) Inhibition of glandular secretion Many glands are innervated by parasympathetic nerves, and their neurotransmitter is acetylcholine, so Botox can inhibit the secretion of glands (sweat glands, salivary glands) by blocking the release of parasympathetic neurotransmitters. (c) Pain relief The mechanism of pain inhibition by Botox may be related to the inhibition of nociceptive afferent nerves, and it is also believed that Botox can inhibit the release of neuropeptide P substance. Therefore, botulinum toxin injection has become the preferred method for the treatment of migraine. (iv) Dilatation of blood vessels It has been reported that botulinum toxin can inhibit vasodilatory nerves and treat vasodilatory diseases. (v), Inhibition of scarring Some studies have shown that Botox has an inhibitory effect on scarring, both in clinical and cytological experiments, showing its inhibitory effect on scarring and fibroblasts. In addition, injection of Botox into the scar or into the muscle around the surgical incision can reduce the pulling effect on the scar and help to reduce scarring.