Normally, dogs have at least one bowel movement every 24 hours, according to "Dog Owner's Home Veterinary Handbook." Constipation is a common and painful condition in dogs. A constipated dog either cannot pass stool at all or passes very small, hard and often dark stool. Constipation occurs more often in older dogs than younger dogs, although dogs of all ages can get it, including newborn puppies. If a dog does not have a bowel movement in 48 hours, please contact a vet.
Make sure the dog drinks more water. This helps the bowels to loosen. Lack of water can cause constipation. If the dog does not seem to be interested in drinking more water out of its regular water bowl, get a second water bowl and place it in a new area of the yard or home. The novelty of a new water source may tempt the dog to drink more.
Add fiber to the dog's regular food. Add 1 to 5 tsp. of wheat bran or psyllium husks for people. Use less for small dogs, more for large dogs. For dogs with teeth problems, soak their kibble or dry food for about 20 minutes in water. Dry food tends to have more fiber than canned or semi-moist food. Give puppies 1 tsp. of olive oil mixed in their canned food. If out of olive oil, give the puppy 1/4 cup to 1/2 cup of cow's milk. Do not give any more or the puppy may get diarrhea.
Put a collar or chest harness on the dog and give the dog more exercise, especially if the dog is elderly. Lack of exercise can cause the bowels to become sluggish.