Artecoll should be injected subdermally, i.e. into the border of the dermis into subcutaneous fat, thereby avoiding a possible visibility of microspheres through the skin and creating a "blanch-effect". While injecting the needle (27G) should be drawn forwards and backwards (tunneling technique) while maintaining constant -pressure throughout the procedure, filling the channels thus created with Artecoll. The injection pressure is correct if the implant flows slowly but evenly and without great exertion. The gray of the needle should never shine through the skin. After injection, the microspheres should be spread and molded with the fingertip to assure an even, subdermal distribution of the Artecoll in the skin. Overcorrection is not advisable; however a second implantation may be necessary after 3 months. The patient should be clearly informed about this by the physician. The volume to be implanted depends on the depth and size of the skin defect or wrinkle and is determined on an individual basis. Strong mimic muscle movement should be avoided in the first days after the implantation, as the microspheres will need 2-3 days to be fixed by fibrous tissue. The use of skin tape is recommended after the treatment. Before using Artecoll a skin test, 14-21 days prior to injection to determine the sensitivity for bovine collagen, is optional.