Every time my dog is let outside, he ends up eating the feces of other dogs.  This is a disgusting habit.  Is it unhealthy, too?

Feces may contain parasites

Coprophagy, or eating feces, is an unpleasant but common behavior of dogs. Unfortunately, dogs can become infected with intestinal parasites by ingesting excrement, which may contain microscopic parasitic eggs. Since your pet has been eating feces, it is very important that your veterinarian evaluate a stool sample to look for infection.

There are several proposed causes for coprophagy. Boredom is one of them; the behavior is more prevalent in dogs that are crated for long periods of time without stimulation. In addition, dogs may eat their own waste as a way of "hiding the evidence" if they receive punishment for inappropriate defecation. Uncommonly, there are also some underlying medical conditions that are thought to be associated with coprophagy, such as a poor diet that is lacking in essential nutrients or vitamins. The problem also may be caused by a pancreatic enzyme deficiency.

Some behavioral experts feel that coprophagia may be related to a dog’s instinctual nature to scavenge for food. It is also possible that dogs eat their feces as a way of playing, learning, and sampling their environment.

Treatment of this problem can be challenging. The first step is to keep the area where the dog voids meticulously clean. This often means following the dog and immediately cleaning up the stool.

In addition, covering the stool with an ingredient that the dog dislikes may be helpful. Compounds such as red pepper sauce or bitter-tasting substances, which are available in pet stores, may discourage dogs from eating  feces. You can also try sprinkling dog food with Accent meat tenderizer or MSG—monosodium glutamate—since these products may help discourage the eating of stool.

Try to deter your dog from this behavior early on, before it becomes a habit that is difficult to control.