Accumulation of dirt; rolled in something smelly

Always check for obvious causes. If your dog has been a long while without a bath, that might be your culprit. Or if you've been to the beach or in the woods, your dog may have rolled in something. A bath is the best solution.

Dental issues

Look in your dog's mouth. Teething puppies often have bad breath, but this is usually normal and passes after teething is completed. Discolored teeth, red and swollen gums and an odor that goes beyond the usual "doggie breath" can be signs of a problem. If you notice these, see your veterinarian for a dental checkup and treatment. Your veterinarian can also explain how you can clean your dog's teeth to help avoid future dental problems.

Ear infections

Ear infections can be the cause of an offensive odor, especially among long-eared and floppy-eared dogs. The inside of the ear becomes moist and hot, providing the perfect environment for infections. Take a close look inside your dog's ears for red and sore skin, and note if your dog cries out in pain as you try to examine the ears. Any of these may be signs of an ear infection which should be treated by a veterinarian.

Skin conditions

Do you feel a slight greasiness on your hands after you pet your dog? This may be an indication of seborrhea, a common skin condition in dogs. These dogs have excess production of sebum, a normal product of the skin glands. The result can be flaky dandruff or an oily, waxy feel to the hair coat and a strong odor. Seborrhea may also dispose a dog to skin and ear infections. Frequent bathing with a medicated shampoo recommended by your veterinarian can help minimize the odor.

Soiled fur

Longhaired dogs sometimes have a soiled rear from defecating. Without daily brushing, the rear can become matted and smelly. Monthly clipping around the rear end helps, as do daily brushing and grooming.

Infected glands

Infection or improper emptying of the anal glands can cause odor and discomfort to the dog and a trip to the veterinarian is in order. Signs include a dog scooting his or her rear end on rough surfaces.

Flatulence

Dogs can get gas too. Unless it is extremely severe, it's probably nothing to worry about. But to help reduce the likelihood of this issue, you should exercise your dog and feed a high-quality dog food. Exercise keeps things moving rather than allowing gas to build, and low quality foods can lower digestibility rate and produce gas. For the best results for your dog, allow at least an hour before and after a meal before exercise.