Why Does My Dog Have Mucus in His Eyes?

Eye mucus is common in dogs — however, excessive discharge (especially when it’s yellow or yellow-green) is a sure sign of trouble.

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Bacterial conjunctivitis, a cause of excessive eye mucus, can be highly contagious, so if you know your dog is infected, keep him away from other dogs and even human family members. By: jonkriz

Eye mucus in dogs is normal and can be caused by a number of things, from viruses to allergies.

However, excessive discharge (especially when it’s yellow or yellow-green) could be a sign of an infection, glaucoma or other eye problems — even a brain or nerve injury.

Learning more about the most common causes of excessive eye discharge will enable you to help your dog stay healthy. To keep this article simple, we’ll discuss 3 common culprits: conjunctivitis, dry eye and breed issues.


Keep in mind that there are many more possible causes of mucus in a dog’s eyes, so please see your veterinarian for a diagnosis if the discharge seems excessive — or if your dog is squinting and has tender eyes.

3 Common Causes of Excessive Mucus in Dogs’ Eyes

1. Conjunctivitis

According to the book What’s Wrong With My Dog’s Eyes, if you notice your dog rubbing and scratching his eyes, he could have conjunctivitis, an inflammation of the mucus membranes that line the inner surface of the eyelid. This condition can be brought on by trauma, bacteria, viruses, foreign matter or allergies.

Bacterial conjunctivitis can be highly contagious, so keep your infected pet away from other dogs and family members. Check for foreign matter by looking at both your dog’s eyes. Wear rubber gloves and check for pus and mucus that may be causing the irritation.

Flush out the eyes using a saline solution. Then, using a cotton swab, gently remove any remaining mucus. Place a few drops of eyedrops (such as Visine or Artificial Tears) 2 to 3 times a day to help soothe his eyes. This process will usually clear up the eye problem within a few days. If it does not clear up, it’s time to visit your veterinarian — she can determine if your pet has an eye injury to the cornea.

In this video, Dr. Wendy Zimmerman, DVM, CVA, explains more about how to clean a dog’s eyes using an eye wash that’s pet-safe:


2. Canine Dry Eye

This condition stems from eyes’ failure to produce cleansing tears.

Symptoms include mucus and inflammation. Infection is a big risk for dogs with dry eye, and it can be painful. Treatments for dry eye in dogs range from artificial tears (for mild cases) to antibiotics. In severe cases, surgery is sometimes recommended.

3. Breed Issues

Type of breed can also play an important role in a dog’s eye problems.

Flat-headed dogs — such as Pekingese, Bulldogs, Boxers and Pugs — are more likely to have discharge because their eye sockets are more shallow and their eyes protrude more.

Breeds with loose facial skin (including Cocker Spaniels, Bloodhounds, Beagles and some terriers) are more prone to cherry eye, a condition that occurs when a gland in the eyelid is jarred out of place. Although steroids and antibiotics will help, sometimes surgery is needed.

See Your Veterinarian for More Information

Because excessive eye discharge can be a sign of more serious problems than the ones mentioned above, don’t hesitate to ask your vet about your dog’s eyes.

To help those eyes stay bright and healthy, keep long hair trimmed around the eyes. Also, make sure that shampoo and other irritants do not get into the eyes.

Remember that bacteria feeds on mucus, so when you see a little mucus in the corner of your dog’s eyes, clean it out with a soft, moist cloth to help prevent infection.


This pet health content was reviewed for accuracy by a veterinarian, Dr. Pippa Elliott, BVMS, MRCVS. It was last reviewed and updated Feb. 4, 2019.


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