It's a fact of life: dogs with white faces will most likely have red tear stains. These stains can be caused by food allergies, fleas, overproduction of tears, abnormalities in the tear ducts or any number of reasons. However, you can do a few things to whiten the fur around your dog's eyes.
Mix 1-cup boric acid and 1-cup cornstarch in a large bowl.
Add enough milk of magnesia to make a smooth paste. Mix in one capful of hydrogen peroxide to treat severe stains.
Coat the stained area with paste using a toothbrush.
Allow the paste to dry before brushing it out.
Wipe the area with a clean cloth to remove excess powder.
Mix 1-cup boric acid powder and 1-cup cornstarch.
Apply the powder to the stained area. Pat gently for surface stains or use a soft toothbrush for stains that spread to the dog's facial features (long hair, moustaches). Allow the powder to stay in the fur for several minutes.
Brush excess powder from the fur.
Boil distilled water. Remove from heat and allow to cool.
Add 1 tbsp of boric acid powder for each cup of boiled water. Stir until all crystals are dissolved.
Add seven swabs per dog being treated to a plastic container.
Pour the boric acid solution over the cotton swabs. Cover the container. Store the container in a cool place.
Use one swab daily to clean your dog's eyes.
Boric acid powder is also known as boracic acid powder or orthoboric acid. A low dose of tetracycline or other broad spectrum antibiotic changes the chemical make-up of the dog's tears. A 10-day course of tetracycline prescribed by a veterinarian can prevent red tear stains from forming or from continuing to form. Fruit-flavoured or plain antacid tablets also change the pH of the dog's tears. Give the dog one-half a tablet (small dogs) up to one tablet (large dogs) daily to prevent staining. If the tablets do not work, try adding 1 tsp of white vinegar or apple cider vinegar to the dog's drinking water. Environmental irritants can cause excessive tearing to occur even when no other physical issues are present. If your dog suddenly develops tear stains, attempt to identify new things that may have been introduced to its environment. Avoid feeding kibbles with corn as a first ingredient or foods that contain additives or artificial colours. If you cannot find boric acid or feel uncomfortable using it, eliminate it from the paste mixture and increase the amount of hydrogen peroxide.
Avoid getting paste or powder containing boric acid into the dog's eyes. Do not allow your dog to ingest paste or powder containing boric acid. It won't kill your dog, but it may feel sick for a while. Do not use the same swab to treat more than one dog. Do not use the same end of the cotton swab to treat both eyes. Do not dip the swab back into the boric acid solution to re-wet it.