Excessive tearing in dogs can have several causes:
Breed or eye shape: Some dog breeds, such as Pugs or Shih Tzus, have larger or more prominent eyes, which makes tears more likely to run down the cheeks.
Blocked tear ducts: Tears cannot drain properly through the nose and therefore overflow.
Irritation: Hair, dust, pollen, or other small irritants can cause the eyes to water.
Infections or inflammation: Suddenly red eyes, mucous discharge, or an unpleasant smell may indicate an infection.
What you can do yourself:
Keep the eye area clean and dry by gently wiping away tears. Always use a clean cloth when doing this.
Carefully trim any hairs that may rub against the eyes.
When to see a veterinarian:
If watery eyes are accompanied by redness, pus, swelling, or pain, or if they suddenly worsen, have your dog examined by a veterinarian.