Human based shampoos are designed to remove all the oils and can be very harsh on a pet's skin. Adult dog shampoos are formulated to remove dirt without affecting their necessary oil balance. If you have a puppy, there are special shampoos just for puppies. Puppy shampoo has a different pH and is more gentle for their sensitive skin. While most kitties can groom themselves, in the event your cat does need a little cleaning, be sure to use a shampoo specifically for cats.