5 Types of Dog Eye Discharge (And What They Mean)

Jennifer Coates, DVM
By Jennifer Coates, DVM on Feb. 10, 2023
close-up of a hound dog's eyes

Eye discharge is a common problem in dogs. And while some types are completely normal, others are associated with potentially serious health concerns.

To determine when you need to take your dog to the vet, you’ll need to understand the various types of dog eye discharge and what each may mean.

Common Types of Eye Discharge in Dogs

Let’s take a look at five common types of dog eye discharge and what you should do about them.

1. A Little Goop or Crust

Tears play an essential role in maintaining the health of a dog’s eyes. Tears provide oxygen and nourishment to the cornea (the clear layer of tissue at the front of the eye) and help remove debris from the eye’s surface.

Tears normally drain through ducts located at the inner corner of each eye, but sometimes a little bit of goop or crust will accumulate there. This material is made from dried tears, oil, mucus, dead cells, dust, etc., and is typically clear or a slightly reddish-brown color.

These “eye boogers” are usually most evident in the morning and are often perfectly normal. The amount of eye goop a dog produces each night (or after long naps) should stay relatively constant.

The goop or crust should be easy to remove with a warm, damp cloth. Your dog’s eyes shouldn’t be red, and they shouldn’t show any signs of eye discomfort, such as rubbing, squinting, blinking, or sensitivity to light.

If at any point you notice an increase in your dog’s eye boogers or other worrisome symptoms, make an appointment with your veterinarian.

2. Watery Eyes

Excessive eye watering (epiphora) is associated with many different conditions that range from relatively benign to serious. A few common causes of watery eyes in dogs are:

If your dog’s eyes are just a little more watery than normal, but they look fine in all other respects and aren’t painful, it’s reasonable to monitor the situation for a day or two.

Your dog may have simply received a face full of pollen or dust, and the increased tear production is working to solve the problem. But if their eyes continue to be watery or your dog develops red, painful eyes or other types of eye discharge, make an appointment with your veterinarian.

3. Reddish-Brown Tear Stains

Light-colored dogs often develop a reddish-brown discoloration to the fur near the inner corner of their eyes. This occurs because tears contain a pigment called porphyrin that turns reddish-brown with prolonged exposure to air.

In the absence of other problems, tear staining in this area is normal and is just a cosmetic concern. If you want to minimize your dog’s tear stains, try one or more of these solutions:

Keep in mind that it can take several months for porphyrin-stained fur to grow out and for the effects of any of these remedies to become obvious.

Make an appointment with your veterinarian for an eye examination if you notice any of the following:

  • An increase in the amount of tear staining

  • A change in the appearance of your dog’s tear staining

  • Your dog’s eyes become red and painful

4. White-Gray Mucus

Dry eye (keratoconjunctivitis sicca or KCS) is a condition that usually develops when a dog’s immune system attacks and destroys the glands that produce tears.

With fewer tears, the body tries to compensate by making more mucus to lubricate the eyes. But mucus can’t replace all the functions of tears, so the eyes become red and painful and may develop ulcers and abnormal corneal pigmentation.

Left untreated, KCS can result in severe discomfort and blindness.

If you notice white-gray mucus collecting around your dog’s eyes, make an appointment with your veterinarian. They can perform a simple procedure called a “Schirmer Tear Test” to differentiate KCS from other conditions that may be associated with increased eye mucus production, like a foreign material lodged under an eyelid or inflammation of the ducts that drain tears.

Most dogs respond well to treatment for KCS, which may involve cyclosporine, tacrolimus, artificial tears, and/or other medications. Surgery can also be considered, but this option should be reserved for cases that don’t do well with medical treatment.

5. Yellow or Green Eye Discharge

A dog whose eyes produce yellow or green discharge often has an eye infection, particularly if eye redness and discomfort are also evident.

Eye infections can develop as a primary problem or as a result of another condition (corneal wounds or dry eye, for example) that weakens the eye’s natural defenses against infection. Sometimes what looks to be an eye infection is actually a sign that a dog has a systemic illness or a problem affecting the respiratory tract, nervous system, or other part of the body.

Any dog who looks like they might have an eye infection should be seen by a veterinarian as soon as possible.

Featured Image: iStock.com/Nastasic

Jennifer Coates, DVM


Jennifer Coates, DVM


Dr. Jennifer Coates is an accomplished veterinarian, writer, editor, and consultant with years of experience in the fields of veterinary...

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