A transparent or translucent medical active substance patch is provided that includes a matrix of monolayer or multilayer configuration with at least one active substance-containing layer contained therein and a backing layer connected with the matrix. The patch, having been applied to the skin of a first person, has a lightness color value L1 at a place of the skin covered by the patch which is not less than 50% and not more than 200% of a lightness color value L2, with L2 being the lightness value of the region of skin of the same person which surrounds the applied patch, with the same being true of the skin of a second or any other person, provided that for all the persons mentioned, the L2 of their respective skin is in the range from 5° to 100°, especially in the range from 20° to 90°.