Ultimate Dog

By Sara Seitz - Reading Time: 12 minutes
dog eye discharge

Dog Eye Discharge: What You Should Know

Dog eye boogers are a fact of life. Just like humans, dogs’ eyes produce ocular discharge meant to help cleanse the eye of pathogens and foreign objects. This gunk can often build up in the corner of the eyes, especially after a long nap or a night of sleep.

But not all dog eye boogers are normal. Some can indicate a serious problem such as infection or injury. Other times, eye gunk can be a sign of an internal imbalance that needs to be corrected.

The key to helping your dog find relief from unsightly eye boogers is to understand what normal and abnormal eye discharge look like. Once you know if your dog’s eye discharge represents a problem, you can use the type of discharge to help you identify the cause so your pup can find some relief.

What Does Normal Dog Eye Discharge Look Like?

Normal eye discharge is caused by a type of mucus called rheum. The eye produces rheum as a way to flush out dust, skin cells, oils, and other irritants from the surface of the eyeball. This mixture of debris and mucus collects at the corner of the eye. 

This buildup can coagulate or dry during sleep or restful periods to form eye boogers.

Normal dog eye discharge is white, gray, or brownish. When a dog comes into contact with a lot of irritants, say on a windy day or after running through a pollen-filled field, they are more likely to produce excess rheum. The amount of eye boogers produced can also be determined by the shape of the eye and the dog's genetic predisposition.

As long as the eye boogers are of a normal color and aren't building up to the point that they are irritating the eye, you likely have nothing to worry about.

What Do Abnormal Dog Eye Boogers Look Like?

Abnormal eye discharge comes in multiple forms. Bright green or yellow boogers are a sign of infection. Crusty boogers that buildup on the eyelids or lashes can also be a sign of infection or may indicate injury to the eye or a foreign body that can’t be flushed away.

Red eye boogers are very common in dogs and can lead to tear staining on the fur below the eye. While typically shrugged off by vets as normal for some dogs, this condition more often than not represents an internal imbalance that can lead to more serious problems.

An excess of normal-looking eye boogers may indicate a structural abnormality or blocked tear duct.

If your dog has abnormal eye discharge, it is important to find the cause so it can be remediated. Abnormal boogers are often a sign that your dog is experiencing discomfort. And eye infections that go untreated for too long can cause blindness.

Causes of Abnormal Eye Discharge

Diagnosing what is causing your dog's excessive tears (a symptom known as dog epiphora) or abnormal eye discharge can be a challenge, considering how many factors affect eye goop. Luckily, with a bit of detective work and some help from the vet, pinpointing the problem is usually possible. Once you know what's causing it, you can take steps to help your pup get better.


Dog eye infections are fairly common, with the most common diagnosis being conjunctivitis.

Conjunctivitis, which is often called pink eye in humans, refers to inflammation of the conjunctiva, or the mucus membrane surrounding the eyeball. Various conditions can cause this problem, including viral infections such as canine distemper, bacterial infections, and secondary immune-mediated autoimmune conditions. 

When an infection is at the root of your dog's eye boogers, you'll typically see bright green or yellow goop in the corners of their eyes. This goop will be excessive and thick. You'll also likely notice that the blood vessels in the whites of their eyes are more prominent, and the conjunctiva under their eyelids is redder than normal.

Eye infections can resolve on their own but most often need medications to help them clear up. If red, goopy eyes are just one symptom of many, then it is absolutely worth getting your dog to the vet for a checkup. Even an infection isolated to the eyes can be damaging to your dog’s sight over time, so it's best to have them looked at by a professional.


If your dog’s eye discharge is deep brown or red, or if the fur below their eyes is stained red, then your pup may be suffering from an internal imbalance.

Many people, including plenty of vets, like to dismiss red tear stains as a product of overproductive tear glands. Because tears contain porphyrin, a red pigment produced by the body, it would make sense that more tears would mean more red staining. But research has shown that most dogs with tear stains don’t produce any more tears than dogs without the condition.

Instead, these stains are caused by increased levels of porphyrin in their tears.

Porphyrin is an organic compound that is formed during the energy production of animal cells. This product can be found in the organs, tissues, saliva, and tears of humans and dogs. But our cells aren’t the only things in our bodies that produce porphyrin. The bacteria and yeast living inside us, on our skin, and in our eyes also produce this byproduct during energy production. Some bacteria, especially those known to be inflammatory and pathogenic, produce this red substance at a much higher rate than most beneficial bacteria.

When your dog’s system gets thrown out of whack, these bad bacteria and yeast take over. Often the first sign of this imbalance is reddish epiphora and stained fur around the eyes.


Injuries to the eyeball, especially scratches to the cornea, are very likely to result in excessive eye discharge. This is because the body will react to these traumas by creating more rheum to flush the injured area of pathogens and debris. This is an important process to prevent infection. 

Pain caused by the injury will also result in excess tear production, which can cause the rheum to be flushed out over the eyelids rather than at the corner of the eye. When this happens, crusty eye boogers tend to collect all around the eye and can even result in the eye being crusted shut after a long snooze.

As long as the epiphora remains white or grayish in color, there likely isn’t an infection. However, damage to the surface of the eye presents the perfect opportunity for bacteria to flourish. Even without infection, damage to the eye can cause lasting sight issues. For these reasons, it’s a good idea to have your dog seen by a vet if you suspect an eye injury. 


Similar to an injury, irritation from pollen or foreign bodies in the eye will cause excess rheum production as a means to flush the eye clean. Even if the eye is not directly involved, irritants in the respiratory tract can lead to excess mucus and tear production that will increase the amount of eye boogers seen.

If your dog tends to have more eye boogers at certain times of the year or during certain activities, it could indicate that they are sensitive or allergic to something in the air. Some medications can help relieve these symptoms, as can avoiding the activity or investing in some doggy goggles.

Blocked Tear Ducts

The tear ducts at the inner corners of your dog's eyes are there to drain away tears after they wash over the eye. If something blocks those drainage tubes, then the tears will spill over onto the lower eyelid. This spillage brings with it rheum, which results in eye boogers forming on the eyelashes and down the fur below the corner of the eye.

If you notice a normal-looking eye goop in these places along with watery-looking eyes and wet fur below the eyes, a blocked tear duct is likely to blame. Clearing a blocked duct usually requires surgery, especially if a genetic condition is to blame.

Structural Abnormalities

Blocked tear ducts are just one of many structural abnormalities that can cause excess eye boogers.

Breeds with bulging eyes are much more likely to experience eye irritation, injury, and blocked ducts. Entropion and ectropion, conditions that cause the eyelids to fold in or out abnormally, can also cause problematic eye discharge. Cherry eye, in which the third eyelid pops out over the eye, is another common cause of excess discharge that has a genetic component.

All of these causes require a veterinarian’s help to fix. Although some, such as naturally bulging eyes, may not have a cure.

How to Help and Prevent Abnormal Canine Eye Discharge

Identifying the cause of your dog’s eye discharge is the first step to helping them find relief. For infection, injuries, blocked tear ducts, and structural abnormalities, this usually starts with a trip to the vet.

There, your veterinarian will assess the eyes and provide medication in the case of an infection or injury. Injuries may also require surgical intervention depending on the severity of the laceration or puncture. Blocked tear ducts and many structural abnormalities will require surgery to fix, as well.

If your dog's eye boogers are caused by irritation due to dust, allergens, or other debris entering the eye, then solving the problem requires avoiding the cause or using ongoing allergy medications, or starting allergy treatment.

Fixing Imbalances

Tear stains are a clear sign of imbalances within the body. These imbalances can have a dietary root or be caused by excess stress.

Porphyrin is created when cells in the body break down iron. If your dog is on a homemade diet that contains a lot of liver, sardines, egg yolks, or dark green veggies, then they may be getting an excess of iron through their food. Many commercial kibble diets will add synthetic iron to their recipes in the form of ferrous sulfate, which can result in higher than necessary iron intake, more so than from getting natural iron from whole foods. This problem is most common in cheaper foods that don’t contain enough red meat to provide natural iron.

While diet can be a direct cause of tear stains, it is much more often simply a contributor to imbalances that lead to excess bacterial and yeast growth in the body.

Too much starch in a dog's diet can lead to excess yeast growth throughout the body. Since yeast also produces porphyrin during metabolism, this can quickly lead to red-stained tears. A poor diet can also weaken the immune system and cause imbalances in the gut. These imbalances quickly spread throughout the body and allow bad bacteria to overpopulate the system. Since pathogenic bacteria are more likely to create excess porphyrin than beneficial bacteria, this quickly leads to problems with tear staining.

This same breakdown in the internal biome can also be caused by excess stress.

Interestingly, not all imbalances lead to red tear stains. In some cases, imbalances in the body can present as inflammation of the conjunctiva and goopy eye discharge. Because conjunctivitis is often seen as only a result of infection, many veterinarians don’t take the time to determine the cause and treat all cases with antibiotics. Since antibiotics contribute to gut imbalance, this can easily make the problem worse rather than better.

Whether your dog is experiencing more stress than normal or suffering from the effects of a poor diet, it is your job to help them find balance. Use exercise and routine to help your pet find some peace of mind to reduce anxiety. And upgrade their diet to an improved commercial feed or a homemade raw diet.

For conjunctivitis, it can also be helpful to call on some well-known natural remedies to help reduce inflammation while the body heals. A simple saline solution made with ¼ teaspoon sea salt and 1 cup of distilled water can be used to flush the eye and calm irritation. 

Eyebright, cranberry, calendula, and many other herbs and tinctures are known to support eye health and reduce inflammation of the mucus membranes around the eye. These remedies, which are often given orally, can help your dog find relief faster and will support the microbiome rather than destroy it, unlike antibiotics.

Adding additional antioxidants, probiotics, and omega-fatty acids to your dog's diet can hasten the recovery of the internal biome. These compounds support a healthy immune system while creating an environment that is less hospitable to yeast and bad bacteria.

It’s All In the Eyes

You always know when your dog is trying to tell you something with those big puppy dog eyes. In the case of eye discharge, finding the answer to what those eyes are telling you is easy if you are willing to do a little investigation. 

Bright yellow or green discharge is a clear sign of infection and may indicate the eye has been injured. Goopy or crusty discharge that appears all around the eye could be a sign of a tear duct blockage or some kind of structural abnormality. Excess but normal-looking discharge is likely due to irritants, a new injury, or allergies.

When it comes to red discharge that leaves tear stains, the culprit is likely an internal imbalance. In this case, it is your job to support and rebalance your dog’s system by providing a healthy, meat-rich diet, a low-stress environment, and supplementing with plenty of beneficial probiotics, antioxidants, and omega fatty acids.


Barnard, E., Johnson, T., Ngo, T., Arora, U., Leuterio, G., McDowell, A., & Li, H. (2020). Porphyrin Production and Regulation in Cutaneous Propionibacteria. mSphere, 5(1). 

Cooney, T. D. (2018, December 17). Homeopathy for eye disorders. IVC Journal.

Fyrestam, J., Bjurshammar, N., Paulsson, E., Johannsen, A., & Östman, C. (2015). Determination of porphyrins in oral bacteria by liquid chromatography electrospray ionization tandem mass spectrometry. Analytical and Bioanalytical Chemistry, 407(23), 7013–7023. 

Peña, M. T., & Leiva, M. (2008). Canine Conjunctivitis and Blepharitis. Veterinary Clinics of North America: Small Animal Practice, 38(2), 233–249. 

Ryan Llera, BSc, DVM, & Ernest Ward, DVM. (n.d.). Eye Discharge or Epiphora in Dogs | VCA Animal Hospital. VCA. 

Seo Kang-moon, Park Yong-ho, & Nam Tchi-chou. (1995). Ocular Bacteria and Concentration of Lactoferrin in Poodle Dogs with Tear Staining Syndrome. The Korean Society of Veterinary Clinics, 12(1), 829–837. 

Sara Seitz

Sara Seitz worked in the pet industry for over a decade. In addition to being a certified dog trainer, Sara gained experience working as the general manager of a dog daycare and boarding facility, as the creator and manager of a pet sitting company, as a groomer, and as a dog behavior evaluator. She also has a bachelors in animal behavior from CSU. Currently, Sara works as a freelance writer specializing in blog, article and content writing.

1 thought on “Dog Eye Discharge: What You Should Know”

  1. Perfect timing for this article! Both of my boys started out with puffy, red and watery eyes last week. They have improved but still some drainage.

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top