2) In your dog’s drinking water, add a teaspoon of white cider vinegar. This will help treat the tear stains. It does this because white vinegar will alter the pH of your dog’s tears, meaning the bacteria that causes the stains will not be able to form under their eyes. If your dog doesn’t want to drink the water because of the taste, start out with a lower amount like ½ teaspoon and then work them up to 1 teaspoon.
