In an attempt to maintain a youthful appearance or to reconstruct facial deformities, physicians have greeted new technologies with excitement. In the late 1800 s, shortly after the invention of the syringe, chemical agents were used for facial augmentation. Unfortunately, history has taught us that new technologies must be used with care, because complications can occur, sometimes many years after initial treatment. The first injectable filling agent was paraffin, whose use was abandoned after complications of migration, embolization, and granuloma formation were described. More recently, silicone use was banned by the U.S. Food and Drug Administration (FDA) because of similar complications. In 1981, bovine collagen was the first agent to be approved by the FDA for cosmetic injection. Since its approval, dozens of injectable filling agents have been developed, and many are already FDA approved for cosmetic use. This article will review the highlights of the evolution of facial filling agents.