Absolute Purple Shampoo is the right whitening shampoo for dogs having a white coat with an undesirable yellow or green sheen. The purple base inside this professional shampoo cuts the yellow sheen, and the concentration of the shampoo allows you to obtain the equivalent in quantities of 4 American gallons, so it becomes economical. Every good groomer should have a whitening or lightening shampoo like Wahl's Absolute Purple for white coats.