Eye discharge is a common problem in dogs. Some types are completely normal, while 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.

NOTE! If your dog has experienced trauma to the eye, or if your pet is: squinting or protecting an eye, the eyeball looks abnormal, experiencing excessive redness in the white part of its eye, or unable to completely close its eyes – this may be an “ocular (eye) emergency,” seek veterinary attention immediately.

Five Common Types of Eye Discharge in Dogs

A Little Goop or Crust — Tears play an essential role in maintaining eye health. They 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 out of dried tears, oil, mucus, dead cells, dust, etc., and is typically clear or slightly reddish-brown in color. It’s most evident in the morning and is 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. The eyes shouldn’t be red, and your dog should not exhibit any signs of eye discomfort (rubbing, squinting, blinking, and/or sensitivity to light). If at any point you notice an increase in your dog’s eye goop or other worrisome symptoms, make an appointment with your veterinarian.

Watery Eyes — Excessive eye watering (epiphora) is associated with many different conditions that run the range from relatively benign to serious. Here are a few common causes of watery eyes in dogs:

If your dog has a relatively mild increase in tears, but his eyes look normal in all other respects—and he doesn’t seem to be in any discomfort—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 tearing is working to solve the problem. But if his eyes continue to be watery or your dog develops red, painful eyes or other types of eye discharge, make an appointment with your veterinarian.

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:

  • Wipe the area a few times a day with a cloth dampened with warm water or an eye-cleaning solution that’s made specifically for dogs
  • Keep the fur around your dog’s eyes trimmed short
  • Try giving your dog an antibiotic-free nutritional supplement that reduces tear staining
    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

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 diseases that are associated with increased eye mucus production.

Most dogs respond well to treatment for KCS, which may involve cyclosporine, tacrolimus, artificial tears, and/or other medications.

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 (wounds, dry eye, etc.) 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 another part of the body.

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