A 62-year-old male patient developed generalized argyria following the intake of silver-proteinacetyltannate (Targesin; approx. 60 g in 10 years) as treatment for gastric discomfort. On histological and ultrastructural examination of the skin, silver particles were found not only in the usual locations but also in the Schwann cell, the mast cell, and in smooth muscle cells. This corresponded to chemical analysis, proving the presence of this metal in the skin. In the blood, a level of 0.26 +/- 0.04 ppm silver was found. By means of an equation, attempts were made to demonstrate the reaction process involved in the formation of Ag2S as subjected to the photochemical effect of sunlight.