Cosmetic injections are clinical procedures that use injections to inject biological materials or synthetic biocompatible materials into the dermis or subdermis to reduce skin folds or contour. As far as the injectable materials are concerned, there are two categories of Botulinum Toxin and filler materials that are more commonly used at present. Due to the difference in the principle of action, the scope of application also differs greatly. 1.Botulinum toxin is a bacterial exotoxin secreted by Clostridium botulinum during the reproduction process. The toxin can selectively inhibit the release of acetylcholine at the neuromuscular junction, thus inhibiting muscle contraction and reducing muscle dynamics. It is mainly used in cosmetic surgery to slim the face (injected in the bite muscle) and reduce facial motor wrinkles (injected in the facial expression muscle), such as head-lift lines, crow’s feet at the corners of the eyes, and Kawasaki lines between the eyebrows, etc. It is valid for 6 months. 2, filler materials to increase the amount of tissue, fill the role of depressions or folds, mainly used to repair the lack of tissue (breast augmentation, temple augmentation, nose augmentation, chin augmentation, smoothing nasolabial folds, etc.) and static wrinkles (nasolabial folds, marionette lines, severe forehead lines, crow’s feet, Kawasaki lines, etc.), mainly autologous fat particles and hyaluronic acid (Ruilan), collagen (double beauty). (1) Autologous fat particles injection belongs to autologous tissue transplantation. It is safe without rejection and can beautify and shape the donor area while correcting defects in the recipient area (two birds with one stone). Autologous fat particles are relatively large, permanently viable and inexpensive, and are mainly used for repair of larger tissue defects, such as breast augmentation, temple augmentation, nose augmentation, chin augmentation and smoothing of nasolabial folds (decency lines). (2) Hyaluronic acid (Restylane), also known as hyaluronic acid. Produced by Q-Med, Sweden, it is valid for as long as one year; collagen (Sunmax): produced by Taiwan Sunmax Biotechnology Company, it can last longer, up to 12-18 months. They are all filler materials, expensive and mainly used for more delicate fillers, such as severe forehead lines, crow’s feet, Kawasaki lines, nasolabial folds, marionette lines, etc. Of course, different materials can be combined with each other to complement each other and better utilize their respective advantages, such as Botox + hyaluronic acid/collagen and autologous fat + hyaluronic acid/collagen. It can also be combined with laser and cosmetic surgery to achieve more perfect results.