Why do dogs have watery eyes?

Dogs eyes can run because they have mucus in their eyes, just like people do. They can also run because the dog may have Allergies. If your dog seems to be in a lot of discomfort from allergies, you can give your dog Benedryl, but be sure to talk to your vet first about dosing instructions.

Our vet advised us to get the over the counter antihistimine "Dayhist Allergy" tablets. (Clemastine Fumarate tablets, USP 1.34 mg). It is used for both humans and dogs. It can be found in any drugstore or at 1-800-petmeds (phone#) or 1800petmeds.com for a very inexpensive price. This site also has other alergy meds available for dogs/cats over the counter.