A method for treating psoriasis of the skin of a patient employs topically applying to the affected skin a composition comprising at least one peptide copper complex. In other embodiments, the present invention is directed to such a method where the composition used therefor further comprises certain disclosed active agents, including active drug and active cosmetic substances. In a related aspect, further embodiments of the present invention are directed to compositions comprising at least one peptide copper complex and certain active drug and active cosmetic substances that render the compositions particularly effective in treating psoriasis.