Dear Dr. Fox • I have a problem with one (or possibly two) of my three dogs.

My female (8 years old) eats fecal matter. Now I'm afraid my 1-year-old female Dane is picking up this behavior.

I have tried For-Bid, meat tenderizer (which makes them extremely thirsty) and Stop, which is a tablet to stop stool eating and help with gas odor (it contains acidophilus chlorophyll, garlic, kelp, liver, parsley, peppermint and yucca). Nothing seems to work.

Any suggestions for breaking this disgusting habit would be greatly appreciated. — J.A., Springfield, Mass.

Dear J.A. • Coprophagia (poop eating) is an obnoxious canine addiction that is difficult to control. Dogs who are cage- or kennel-confined and bored often give up this vice when given more freedom and objects to play with.

In your situation, your dog may or may not have some nutritional deficiency. Many dogs stop their coprophagia when taken off big-brand, junk dog foods and are given something better to eat. But your dog may simply be conscientiously cleaning up after your other dogs, just as she might with a litter of pups.

I would suggest you either muzzle your dog so she can't eat anything outdoors or use a remote-control training collar that gives an alarming buzz to inhibit this behavior (but not one that delivers an electrical shock). Adding two tablespoons of plain "live" yogurt (containing live bacteria, not pasteurized) or plain, organic kefir and 1 teaspoon of brewer's yeast (not baker's yeast!) to her food every day may help stop this addiction.

Dear Dr. Fox • I have a 12-year-old cat who has become extremely territorial. An irresponsible neighbor lets her cat out every night, and it comes into my yard. My cat goes absolutely berserk.

I took her to the vet, and they found nothing physically wrong. They wanted to put her on Prozac, but I don't want to drug my cat. Is there some other way to correct this problem? — P.M., Clinton Township, Mich.

Dear P.M. • When resident cats see free-roaming cats invade their territory, it can create a lot of stress in the household. Certain resident cats often get so aroused as to attack another cat in the home or redirect aggression toward a human family member.

Other than finding where the invading feline lives and urging the owners not to let their cat out or making your yard cat-proof with a specially designed fence, the best advice is to put up a screen or curtain so your cat can't see the backyard. At the very least, keep away from your cat when the sight of the intruder arouses her. Let the cat calm down by herself.

www.twobitdog.com/DrFox Dr. Fox, c/o "Animal Doctor," United Features Syndicate, 200 Madison Avenue, New York, N.Y. 10016