My dog has recently started licking and eating the dirt. Why is he doing this? Is it harmful?

Pica is the eating of objects that are not appropriate food substances.

Some dogs will eat or lick some of the strangest things, including dirt, mulch, rocks, fabrics, and even feces. This behavior is called pica. Sometimes an underlying disease will cause it, but in most dogs that demonstrate pica, a behavioral anomaly that may not be completely understood is the most likely cause.

Diseases involving the nervous system such as rabies or neurotoxin exposure may cause pica. Anemia, hypothyroidism, certain diseases of the liver, pancreas and gastrointestinal systems, nutritional problems, and foreign bodies may cause it as well.

Your veterinarian may perform a physical examination, bloodwork (CBC, blood chemistry), and urinalysis to determine if a disease or other physical process is causing the pica. When an underlying disease or disorder is present that causes pica in the affected dog, treatment is directed at the disease process. Ensuring that the diet is appropriate and of good quality will eliminate nutritional deficits as a cause of pica.

When no disease can be found, which is most often the case, pica is considered a behavioral problem. It is often associated with obsessive-compulsive disorder. Pica may also be caused by boredom. The veterinarian may prescribe antidepressive drugs. The veterinarian may refer some affected dogs to a veterinary behaviorist for consultation.

Other treatment revolves around controlling the dog's environment. The owner should prevent the dog's access to the desired substances or objects. Keeping the dog indoors and walking the dog on a leash will help bar access.

In addition, where practical, covering the substance 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 inappropriate things.

Luckily, eating dirt will probably not be harmful to your dog. Eating rocks or other larger objects may damage the teeth and necessitate surgical or endoscopic removal of the swallowed object, but dirt should pass through his gastrointestinal tract without much difficulty. It would be a good idea to have your veterinarian do a fecal flotation examination every six to 12 months. This will screen your dog for exposure to intestinal parasites or worms such as hookworms, roundworms, and whipworms that pass to dogs via contaminated soil.

For more information about pica, please go to our Web site and look in our magazine section for the article titled, "Crazy Cuisine: Eating Disorders of Dogs."

03/14/03