Silicone, a man-made polymer containing the element silicon, has been used in a variety of medical devices including breast implants. Silicone was used, in part, because it was suggested to have the property of biological inertness. Inert materials do not affect chemical, physiological, or immunological processes. Silicone is not inert. Silicone from breast implants "bleeds" through the surrounding envelope and is present in the surrounding capsule or migrates to other distant locations. Silicone and/or the multiple chemical contaminants elicit foreign body reactions associated with granulomatous inflammation and fibrosis. Silicone and its contaminants have the potential for significant toxicity in the implant recipient.