Q: What kind of shampoo is best for my Norwich terrier? Every groomer recommends a different one. Her breeder even suggested I not bathe her at all unless I really had to. And why can't I use a human shampoo?

A: Bathing once or twice a month is sufficient for most dogs, though it's true that dogs with wiry coats (like some Norwich terriers and Jack Russells, for example) can go for months without a bath. If you're extra-sensitive to smells or appearances, more frequent bathing is acceptable.

If you choose to bathe one or more times a week, a delicate shampoo is a wise choice. These are often labeled ``non-soap,'' ``detergent-free'' or ``for sensitive skin.''

They're often best for geriatric dogs and puppies, too.

Beyond these basics, consult your veterinarian about your dog's overall skin quality and health, especially if you notice a change (a dull coat, for example, or increased odor). This could be a sign of underlying disease or, at the very least, a good reason to change your bathing protocol.

In a pinch, you can use a human shampoo on a dog. But on a regular basis, the differences in pH between pet and human shampoos can lead to skin irritation.

Dr. Patty Khuly has a veterinary practice in South Miami and blogs at www.dolittler.com. Send questions to khulyp@bellsouth.net, or Dr. Dolittler, Tropical Life, The Miami Herald, 1 Herald Plaza, Miami, FL 33132.