Implanted silicone breast prostheses leak silicone gel through the intact membrane. In order to determine the exact location and to achieve a semiquantitative estimation of the amount of silicone in the surrounding tissue, a method involving scanning electron microscopy (SEM) and energy dispersive analysis of X-rays (EDAX) was used. By this method we were able to demonstrate the presence of the element silicon (Si) (main component of silicone, a polymer with a general formula e.g. (CH3[Si(CH3)2O]n Si(CH3)3 along the inner border of vacuoles corresponding to the light microscopic localization of droplets and in macrophages. The tissue adjacent to the prostheses had a higher silicon content than the control tissue.