What’s Causing My Dog’s Eye ‘Goop?’

By Dr. Karen Shaw Becker

'Eye boogers,' or ocular discharge, can be puzzling to dog owners, simply because it can change appearance from one day to the next. So, do you just wipe it away or is it ever a reason for concern? Know the seven types of eye discharge, and the types you shouldn't ignore.

Dogs get discharge from their eyes just like humans do. Depending on its color, quantity and consistency — along with other signs and symptoms — it may be normal or a sign of disease, injury or infection.

In general, if you notice your dog rubbing or pawing at his eyes, or he suddenly starts squinting, you should see a veterinarian to rule out infection or injury. A lot can be learned, however, by getting familiar with some common types of discharge you may notice from your dog’s eyes.

7 Types of Eye Discharge in Dogs

1. Yellow or green eye discharge — This is often a sign of an infected eye. The infection may be due to bacteria or an underlying condition, such as corneal wounds or dry eye. Often, your dog’s eyes will also be red and painful, so you may notice your dog rubbing his eyes on the couch or pawing at them.

Conjunctivitis, or inflammation of the eye lining commonly known as pink eye, can also lead to green or yellow discharge. This condition can be triggered by allergies, injury or dry eye. If the pink eye doesn’t clear up after a day or two, doesn’t respond to treatment or is accompanied by cloudiness in the cornea, you should see your veterinarian for follow-up.

2. Thick, yellow discharge — Pets with keratoconjunctivitis sicca (KCS), or dry eye, may have thick, yellow discharge from their eyes. It may have a gummy texture and cause his eyelids to stick together. This occurs because the tear mixture consists mostly of oil and mucus instead of water.

The most common cause of KCS in dogs is immune-mediated inflammation and tissue destruction in tear-producing glands, a problem often seen in cocker spaniels, miniature schnauzers, and West Highland white terriers. Brachycephalic breeds (breeds with short muzzles and bulging eyes), such as the Cavalier King Charles spaniel, English bulldog, Lhasa Apso, pug and Shih Tzu are also predisposed to KCS.

3. Watery eyes — Epiphora is a term used to describe watery discharge or excessive tearing. It’s typically due to eye irritation, caused by a foreign object or dust, for example, or abnormal tear drainage. If the excess tearing goes away after a brief episode, it was likely due to an irritant.

Chronic watery eyes, however, may be a sign of blocked tear ducts and corneal wounds. Viral conjunctivitis, glaucoma, allergies or a structural abnormality of the eyelid or eyelashes can also cause watery eyes. The latter includes

  • Entropion — The lower eyelid folds inward, resulting in pain, irritation and excessive tearing.
  • Trichiasis — Eyelashes grow in the wrong direction, causing pain and irritation.
  • Ectropion — A condition in which the lower eyelid droops or rolls out from the surface of the eye, causing irritation and watery eyes.
  • Distichiasis — Excessive eyelash hairs growing from the dog's eyelids rub against the cornea, irritating it. The affected eye becomes red, inflamed and may develop a discharge.

  • 4. Reddish-brown tear stains — Tear stains are caused by a pigment in tears called porphyrin, which turns a reddish-brown color after exposure to air. It’s more obvious on dogs with white or light-colored faces. As long as no other symptoms are present and your dog isn’t bothered by the discharge, tear staining is primarily a cosmetic issue.

    To prevent tear stains, wipe your dog’s face with a warm, damp cloth at least twice a day to help clear away porphyrin-containing moisture. Keeping her face hair trimmed is also important, as is periodic detoxification. I’ve also found fresh-fed dogs have far less severe tear staining than dogs consuming only ultraprocessed food, so diet is a contributing factor, in my opinion.

    5. Slight crusty goop — Ocular discharge, otherwise known as “eye boogers,” is a normal occurrence due to tears accumulating in the inner corner of the eye, leading to a small amount of crust or goop. You may notice it most often in the morning, and it’s not a cause for concern. If you notice an increase in eye goop, or it’s accompanied by signs of pain or itchiness, you should get it checked out, however.

    6. Pink or red eye discharge — This may be due to an injury, leading to blood-tinged discharge. A type of yeast known as Malassezia pachydermatis is also associated with corneal ulcers, which can cause a reddish discharge. If your pet has a corneal ulcer, the conjunctiva of her eye — the pink tissue that lines the undersides of the eyelids — will turn an angry red color.

    There may also be some swelling. If the condition is painful, your dog will show signs of discomfort like squinting or pawing at her face.

    Your pet might also have a scratch or other wound on the surface of her eye caused from contact with a plant or bush, a scratch from another animal, chemical irritation (from shampoo, for example), or a foreign body that gets caught under an eyelid and rubs abrasively against the eye. Your dog or cat can also self-injure by rubbing or scratching her head or ears.

    7. Mucus or pus-like discharge — Your dog has a third eyelid in the corner of each eye, located underneath the lower lid. It houses a tear gland and, when healthy, remains tucked away and can’t be seen by looking at your dog. Sometimes, the gland may pop out or prolapse, leading to a bright red bulge known as cherry eye. This may be accompanied by a mucus- or pus-like discharge.

    While cherry eye isn’t typically painful to dogs, once the gland pops out it can become increasingly inflamed and is vulnerable to infection. An aggressive holistic protocol may help control inflammation associated with this condition, but gland replacement may be required.

    Keep in mind that your dog’s eyes reveal clues to his overall health. Many chronic conditions may manifest in the eyes. Anytime you notice an unusual eye discharge, see your veterinarian to rule out a health condition.

    Consulting with a veterinary ophthalmologist for complicated cases is another option to ensure you haven’t missed anything. Often, eye conditions are treatable when caught early but can progress to permanent injury or vision loss if left untreated.