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, I’ll discuss 3 common culprits: conjunctivitis, dry eye and breed issues.

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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.

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See Your Veterinarian for More Information

Because excessive eye discharge can be a sign of more serious problems than the ones I mentioned above, don’t hesitate to ask your own 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.

Gayle Hickman

View posts by Gayle Hickman
Gayle Hickman has been researching and writing about pet behaviors since 2011. In addition to Petful, her articles have appeared on Reader's Digest, Yahoo Shine and WebVet, to name a few.

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  1. koathebarbarian
    April 2, 2013

    my dog’s eyes are clear but today he has had some yellowish green mucus coming out from the inside corner of his left eye. I’ve cleaned it out twice with about 2 hrs between and it been about another couple hours and there seems to be more but not nearly as much. It seems to be going down after every cleaning. His eyes have been clear the whole time. He isn’t scratching or pawing and shows no sign of discomfort. He’s droppings look normal as well. Show i take him to the vet? or should i wait to see if it does clear up? any suggestions?

    1. Pets Adviser
      April 3, 2013

      Keep in mind, this is not veterinary advice, but is for informational purposes only.

      If the eye isn’t red, and if he isn’t pawing at it and keeping it closed, you can probably watch it for 24 hours — but be extremely cautious when it comes to eyes. If he still has a discharge with a green to yellow discharge after 24 hours, this will likely not get better on its own, so in that case, go to the vet. This usually means a bacterial infection; the cornea should be checked by the vet to make sure it doesn’t have a scratch; he will probably go home with ophthalmic medication.

    2. joyce
      June 26, 2014

      I’ve only read briefly that certain dog foods can cause this too, even for humans I’ve heard Dr Oz say too much cholesterol can cause mucous in the eyes of humans.. planning on doing some research on this topic TODAY.. but just a suggestion.

  2. jordan
    June 9, 2013

    my dog has a gooey green substance in his it was covering alot of his I yesterday and i just cleaned it out again
    what should i do besides the vet if i really need to go then i will take him

    1. Kristine Lacoste
      June 12, 2013

      Hi Jordan,

      Gooey and green makes me think an infection might be present, but there could be other reasons. I definitely recommend a trip to the vet.

  3. vicki
    August 10, 2013

    my pug dogs eye is cloudy and has white runny stuff coming out of it i keep wiping it will it go better on its own as i cant afford vets what shall i do plz love vicki x

  4. AZ
    December 20, 2013

    My 3-year old lab mix has thick yellow gunk coming out of both her eyes. I wipe it away and it comes back within a few hours. It’s been this way for 48 hours now. She has all her usual energy, eats with the same excitement, constantly wants to play, gets the same level of tired after our walks and exhibits no other symptoms. Can dogs get colds?

  5. Gregory Shockley
    December 23, 2013

    We just bought a puppy 2 days ago. Today his left eye has thick clear/white goopy discharge. It was dried up holding his eye closed. We wiped it off w/a warm rag. More goop came out. Is this something that should be taken to a vet or just use an eye dropper?

  6. kendra
    December 30, 2013

    My yellow lab has been shutting her eyes alot and has constant boogers in her eye… what should i do?

  7. Breze
    January 7, 2014

    My 8 month old mastiff started having cold symptoms the other day and I didn’t think much of it but now his eyes are really bloodshot and he’s squinting as if in pain. They are also seeping some greenish yellow stuff an when I wipe it it comes back within minutes. What can I do to help him?

  8. Bernadette V. Kelekolio
    January 16, 2014

    (Please keep in mind I told my mom to see the vet but she wanted me to check internet any way.)
    My moms dog has cataract not sure which or if both eyes have it. But recently he started having thick greenish mucous like discharge from his left eye only. He won’t let anyone clean his eye. He gives a warning like snap than he’ll walk away. I couldn’t really find anything on the internet that was of any real help. Your input would be greatly appreciated.

  9. CatDog
    January 20, 2014

    I have a 12yo. Female Pit/Basset. She has an eye from each breed. Her Pit eye, right side, constantly has clear/yellow damp discharge that I wipe clean 2-5 times a day. It is staining the fur on the inside corner. Bottom lids are pink in color.Her Basset eye, left side has dark crunchy discharge that usually only requires cleaning in the morning. more if she sleeps longer during day. Bottom lid on this side looks black to me, as a trait color of a Basset Hound eye would look like,? Can I use people eye drops on her? Ant other suggestions, tips ? Thanx

  10. Wally
    May 17, 2014

    I have a Yorkie, his eyes have a yellow discharge from the inner corner. He’s been scratching his body, head and eyes until they bleed. I changed his diet thinking he was allergic to his new food, now he’s eating BLUE for the last week. I placed a cone on him to stop his scratching and give him a small amount a Benadryl he’s not getting better. His attitude, playfulness is the same. Today he just started sneezing, could he have a bad cold or is this more serious?

  11. Hi!
    May 26, 2014

    My American bulldog/labrador retriever mix has a lot of brownish eye discharge with red eyes. Since she is part bulldog, is it a breed issue or does it have something to do with her red eyes?

  12. Samuri
    June 6, 2014

    My older dog – Ive had her 8 years but she was an adult rescue – has thick yellowish discharge from both eyes. She finished two rounds of Neomycin and Dexamethasone Opthalmic Suspension. Whenever the drops stop, the goo comes back. My vet is on vacation; what do I do now? She looks miserable. Thanks.

  13. Julie
    June 16, 2014

    My dog was sprayed by a skunk about a week ago and ever since there has been discharge in one of his eyes, started out kind of yellow but now is green. Yuck! So it’s getting worse and I hate to go to the vet but they will never prescribe something without seeing the vet – $$$ scam or is it liability? Anyway, I’m wondering if I can do this at home. Do you think I should put a warm compress on it and/or rinse with an eye irrigation solution or Systane lubricating drops? I’m not positive that it’s from the skunk but I think it’s likely. Thanks much in advance for your reply.

  14. Nichole Casto
    June 16, 2014

    My seven month old Australian shepherd mix Brody has had for the past couple days increased mucus and yellow discharge coming out his eye. I clean with a wet wash cloth making sure its clean multiple times a day. He has short hair so hair is not the issue. He does have distichiasis but what;’s odd is its worse in the opposite eye. I have been keeping check on his eyes closely because of his distichiasis to see if something arises. But it is on his left eye that only has a couple inward eyelashes and it has been producing a lot of discharge sometimes it cakes up where his eye lids are stuck together. The inside of his eye is kind of pink but it is not swollen or soft and doesn’t seem painful to him. I am a college student and would prefer to know if I have any other options besides taking him straight to the vet. But here is a picture of him so you can see its not his hair or anything like that interferring.

  15. David Elfin
    June 25, 2014

    My 7-year-old cocker whom I rescued last year has chronic, excessive yellowish discharge in her eyes. The vet has seen her a couple of times and is concerned that her cataracts may eventually cause her to go blind. Do you recommend having them removed and would that stop the discharge?

  16. Lala
    June 29, 2014

    I have a mutt dog, but poodle and Chihuahua is clear in him, and clear to the family who sold him to us. He is still a puppy, and as most poodles he has a strip of fur underneath his eyes that is covered in eye junk, should I be worried? Should I take him to a vet about this matter? Should I leave it alone? I don’t know really…

  17. Brian Pyne
    November 12, 2016

    When my dog, a Terrier/Collie cross feels ‘a degree under’ his left eye produces a small amount of mucus. He is now 15 years old (and 1 month). Apart from arthritis, mainly in his left foreleg, and a bit of dementia, he seems quite happy an healthy.
    The mucus thing does not appear to be age related as id has occurred on and off over several years.
    I am just curious really, if anyone has a dog that exhibits the same thing

    1. Melissa Smith
      November 13, 2016

      Hi Brian! I have a couple of clients (I’m a pet sitter) that have occasional eye boogers/mucous. In their cases it’s never a big deal, just a tissue swipe and on with their day. Probably couldn’t hurt to mention it at your dog’s next vet appointment, just in case. Some mucous-y conditions get eye ointment but lots don’t.

      1. Brian Pyne
        November 13, 2016

        Thanks for that Melissa. I don’t see it as a real problem, but I will mention it when we are at the vet next.
        Cheers for now and thank you for your observation.

        1. Melissa Smith
          November 15, 2016

          No problem Brian – I hope it helped!

  18. Zak17
    January 8, 2017

    my dog (a red heeler/mini australian shepherd cross) has pretty well constan eye mucus. could this be because she only has her first set of shots?

    1. Dr. Pippa Elliott, BVMS, MRCVS
      Pippa Elliott
      January 10, 2017

      Hi Zak,
      Interesting. I would suspect the mucus is unrelated to her shots, but when she goes for the next one definitely get the vet to take a look. What color is the mucus? If it’s greeny-yellow, this is a sign of infection, which would need checking out. Also, take a look at the whites of the eye. Do they look bright and clear? If so, and the mucus is white or clear, then it could be your pup just isn’t used to cleaning her own eyes (Mom used to do it for her.) But again, if the whites are inflamed, this could be due to irritation, allergy, or infection so a checkup is a good idea.
      Woofs and wags to your pup!
      Dr P


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