Pigmentation depends on the presence and relation of reddish phaeomelanin and black eumelanin, and the density and distribution of the melanins in the hair cortex and/or the hair medulla as well as along the hair shaft. However, discoloration of the coat seems to be a problem of practical importance in canines. This includes general fading of hair colour but also yellowish or reddish hairs in white or black individuals. The article gives an overview on important nutritional influences on hair colour, that may also affect hair structure. In this connection, specific amino acids (above all tyrosine, phenylalanine), trace elements (above all copper, zinc), and vitamins (above all B complex, B-2, H) are of particular significance for the appearance of the coat.