. Often two applications of shampoo are recommended which allows degreasing and removal of superficial scale at the first application and increased penetration at the second. Prolonged exposure to the active ingredients before rinsing allows penetration and is particularly important for keratoplastic action and to permit penetration of active ingredients in the hair follicles. Manufacturer’s instructions on the duration of exposure should be carefully observed except in animals with sensitive skin when the duration of treatment should be reduced.