# Dog Eye Tearing and Tear Stains: Causes and Care Dog eye tearing happens when tears spill onto the face instead of draining normally through the tear ducts into the nose. It can be a harmless breed trait, or it can signal a blocked duct, an injury, or an infection that needs treatment. This article is educational and is not a substitute for veterinary diagnosis or treatment. ## Quick Answer - A little clear wetness at the inner corner is often normal, especially in flat-faced breeds and small white dogs. - Overflowing tears, brown or reddish stains, or a dog who keeps pawing at one eye point to a cause that should be checked. - Tear staining is usually cosmetic, but it can also reflect an underlying eye or tear duct problem [1]. - Any squinting, cloudiness, sudden swelling, or a red mass in the corner of the eye needs a same-day vet call. - Never put human eye drops or leftover pet medications in your dog's eye unless your veterinarian tells you to. ## What Dog Eye Tearing Looks Like and What Is Normal Tears are made by the lacrimal gland at the top outer edge of the eye, and they drain through the nasolacrimal ducts into the nose [2]. When that drainage works well, you rarely see tears on the face. When it slows down or tears are produced faster than they can drain, the eye "weeps" and the fur below the eye stays damp. Normal tear production in dogs is often measured with a Schirmer tear test. In healthy brachycephalic dogs (flat-faced breeds), median values sit around 20 mm/min [3]. A value above roughly 25 mm/min suggests epiphora, which means tears are overflowing because of excess production [4]. Some wetness is simply how your dog is built. Flat-faced dogs have shallow eye sockets and short tear drainage paths, so tears spill more easily. Small white breeds like Poodles and Bichons are also prone to visible tear staining [1]. What is not normal: a sudden change in one eye only, tears mixed with pus or thick mucus, or a dog who squints, rubs, or holds the eye closed. Those signs mean something is irritating or injuring the eye itself. ## Why Is My Dog's Eye Tearing? Main Causes | Cause | Typical clues | How urgent | |---|---|---| | Blocked or narrow tear duct | Constant clear weeping, often one eye, no pain, no redness | Routine visit | | Cherry eye (prolapsed gland) | Red, swollen mass at the inner corner, pus-like discharge possible | Soon, within days | | Injury or foreign object | Sudden tearing, squinting, pawing, redness, one eye only | Same day | | Infection or inflammation of the tear sac | Swelling near the inner corner, discharge, tenderness | Same day to 48 hours | | Allergies or atopic dermatitis | Both eyes watery, itching, skin and ear issues | Routine visit | | Dry eye (KCS) | Thick discharge, dull eye, tearing that looks like overflow | Same day to 48 hours | | Breed anatomy | Lifelong mild wetness, flat face or shallow sockets | Routine visit | | Tear staining | Brown or reddish fur below the eye, no pain | Routine visit | ### Blocked Tear Ducts The nasolacrimal ducts carry tears from the eye into the nose [2]. If a duct is blocked, narrowed, or was never fully open, tears have nowhere to go and spill over the lower lid. This often shows up as one eye that always looks wet while the other stays dry. Some dogs are born with this, and others develop it after infection, a foreign object, or trauma [2]. ### Cherry Eye Cherry eye is common in young dogs and in breeds such as the American Cocker Spaniel, Lhasa Apso, Beagle, Pekingese, and English Bulldog [2]. The gland of the nictitating membrane slips out of place and sticks out as a red, swollen mass next to the lower eyelid [2]. A pus-filled discharge may appear too [2]. The swelling can shrink for short periods, but the gland usually stays dislocated [2]. ### Injury and Foreign Objects A scratch from a cat, a grass seed, a burr, or a piece of grit can all make one eye tear heavily and hurt. If your dog is squinting or rubbing, treat it as an injury until a veterinarian says otherwise. For more on telling these apart, see [Dog Eye Injury: Redness, Swelling, or Discharge?](/knowledge/veterinary-medicine/online-vet-and-care-costs/dog-eye-injury-redness-swelling). ### Infection and Inflammation Inflammation of the tear sac, called dacryocystitis, can cause swelling, discharge, and tenderness near the inner corner of the eye [2]. Infections of the conjunctiva or cornea can also increase tearing. Discharge that turns yellow, green, or thick is a sign to call your vet. Our guide to [Dog Eye Discharge: Normal or Infection?](/knowledge/veterinary-medicine/online-vet-and-care-costs/dog-eye-discharge-normal-or-infection) walks through the differences. ### Allergies and Skin Disease Dogs with atopic dermatitis often have altered tear production. In one study, 21 of 47 atopic dogs had Schirmer tear test values outside the normal range in at least one eye, and three had values above 25 mm/min, consistent with epiphora from excess tearing [4]. If your dog also itches, chews paws, or has ear infections, allergies may be part of the picture. ### Dry Eye (KCS) This one surprises owners. A dry eye can actually look wet because the eye produces a poor-quality tear film and responds with irritation and discharge. Dry eye is a disorder of the tear system and can follow damage to the glands or ducts [2]. It needs a veterinarian's diagnosis, not home remedies. ### Tear Staining Tear staining is common and often underestimated, and it may reflect underlying disease [1]. The color comes from porphyrins, pigments that contain iron. In a study of Poodles and Bichons given diets supplemented with certain herbal extracts, tear staining decreased, and the effect appeared linked to changes in gut bacteria and iron and porphyrin metabolism [1]. That does not mean herbs are a treatment you should try on your own. It does mean staining is worth mentioning at your dog's next exam. ## Red Flags: When Dog Eye Tearing Is an Emergency Call an emergency clinic right away if you see any of these: - The eye is closed, squinting, or held shut. - Your dog is pawing at the eye or rubbing it on furniture. - The eye looks cloudy, blue, or different in color from the other eye. - There is sudden swelling, bleeding, or a wound near the eye. - A red mass has appeared at the inner corner (possible cherry eye) [2]. - The eye bulges or looks larger than normal. - Your dog yelps when the eye area is touched. - There is thick yellow or green discharge along with pain. These signs can point to a corneal ulcer, a foreign object, glaucoma, or another condition where hours matter. Do not wait to see if it improves overnight. ## Safe Things You Can Do at Home While You Wait You cannot diagnose the cause at home, but you can keep your dog comfortable and avoid making things worse. - Keep the area clean. Gently wipe the fur below the eye with a clean, damp cloth or cotton pad soaked in plain warm water. Use a fresh pad for each eye. - Do not touch the eyeball. Wipe only the skin and fur around the eye. - Stop your dog from rubbing. A soft cone or an inflatable collar can prevent pawing until you see the vet. - Check for obvious irritants. Look for a hair, seed, or burr near the eye, but do not try to remove anything stuck to the surface. - Skip human products. Do not use human eye drops, saline with preservatives, or leftover medications from another pet. - Note what you see. Write down which eye, when it started, and whether there is discharge, squinting, or odor. This helps your vet. If your dog has a known allergy diagnosis, keep following the plan your veterinarian already set. Do not add new supplements or foods on your own, since the dose and product choice depend on your dog's weight and health. ## What Your Veterinarian Will Check and Test A tearing eye gets a full eye exam, not just a look at the wet fur. Your vet will start with a general eye exam and may use a fluorescein stain to check for scratches on the cornea. A Schirmer tear test measures tear production, and values above about 25 mm/min point toward epiphora from excess tearing [4]. Normal values vary with breed, and healthy flat-faced dogs often sit around 20 mm/min [3]. If a blocked tear duct is suspected, your vet may flush the nasolacrimal system to see whether fluid passes into the nose [2]. This can be both diagnostic and, in some cases, part of treatment. Tear film health can be assessed in other ways too. Tear film break-up time, tear meniscus height, and osmolarity give a fuller picture of the tear film, and these measures are being studied in both brachycephalic and non-brachycephalic dogs [3][5]. Tear fluid itself contains proteins that researchers are studying as markers of eye and other diseases, though this is not yet a routine test in general practice [6][7]. If allergies are suspected, your vet may ask about diet, itching, and past skin or ear problems. In atopic dogs, tear production can fall outside normal ranges, so screening may be worthwhile [4]. ## Preventing and Monitoring Tear Problems You cannot prevent every cause of dog eye tearing, but you can catch problems early. - Know your dog's normal. Look at both eyes each week. One wet eye that stays wet is more concerning than two mildly damp eyes. - Keep hair trimmed. Long hair around the eyes traps moisture and irritates the surface. Ask your groomer to keep it short. - Manage allergies with your vet. Atopic dogs may need ongoing skin and eye care, and tear production can shift with their condition [4]. - Watch staining over time. If stains get darker, spread, or come with discharge or odor, book an exam. Tear staining can reflect underlying disease [1]. - Follow up on duct problems. Blocked ducts and cherry eye often need monitoring or treatment, and the gland may stay dislocated even when swelling goes down [2]. - Keep routine eye checks. Senior dogs and flat-faced breeds benefit from regular exams, since tear film stability can be reduced even when tear production looks normal [3]. For a broader look at what different discharges mean, see [Dog Eye Discharge: When Should You Worry?](/knowledge/veterinary-medicine/symptom-guides/dog-eye-discharge-when-to-worry) and [Dog Eye Discharge Goop](/knowledge/veterinary-medicine/symptom-guides/dog-eye-discharge-goop). ## Limitations and When to Contact a Veterinarian This article cannot tell you what is causing your dog's tearing. Only an exam can do that, and individual cases always need a veterinarian. Call an emergency clinic now if your dog is squinting, holding the eye closed, pawing at the face, has a sudden red mass at the inner corner, or has a cloudy or bulging eye. These signs can mean a corneal ulcer, a foreign object, or increased pressure inside the eye, and they should not wait. Call for a same-day appointment if tearing started suddenly in one eye, if discharge is thick or colored, if the area near the inner corner is swollen, or if your dog seems uncomfortable. Schedule a routine visit if the tearing has been mild and steady for weeks, if you notice brown or reddish staining, or if your dog has a known allergy or flat-faced breed and you want a baseline eye check. ## Frequently Asked Questions ### Why does my dog's eye keep tearing? Constant tearing usually means tears are overflowing because of a blocked or narrow tear duct, excess tear production, or an irritated eye surface. Breed anatomy plays a role in flat-faced and small white dogs. A vet exam can separate a harmless trait from a duct or eye problem. ### Are dog tear stains dangerous? Tear stains themselves are cosmetic, but they can reflect an underlying condition, and staining is often underestimated for that reason [1]. If the stains come with discharge, odor, redness, or squinting, get the eye checked. Otherwise, mention it at your next routine visit. ### Can I use human eye drops on my dog? No, not without your veterinarian's approval. Human drops may contain preservatives or medications that are not right for dogs, and some can worsen an eye injury. Keep the area clean with plain warm water and let your vet choose any medication. ### Does a blocked tear duct fix itself? Sometimes a young dog's duct opens with time, but many blocked ducts need treatment. Your vet may flush the duct to check whether fluid reaches the nose [2]. If the blockage persists, your vet will discuss options based on your dog's specific case. ### Should I worry about one watery eye? Yes, one-sided tearing deserves more attention than tearing in both eyes. It often points to a foreign object, an injury, or a duct problem on that side. If the eye is also squinting or red, treat it as urgent and call your vet the same day. ## Related Articles - [What Is Dog Eye Discharge](/knowledge/veterinary-medicine/symptom-guides/what-is-dog-eye-discharge) - [Dog Eye Injury: Redness, Swelling, or Discharge?](/knowledge/veterinary-medicine/online-vet-and-care-costs/dog-eye-injury-redness-swelling) - [Dog Eye Discharge Goop](/knowledge/veterinary-medicine/symptom-guides/dog-eye-discharge-goop) - [Dog Eye Discharge: Normal or Infection?](/knowledge/veterinary-medicine/online-vet-and-care-costs/dog-eye-discharge-normal-or-infection) - [Dog Eye Discharge: When Should You Worry?](/knowledge/veterinary-medicine/symptom-guides/dog-eye-discharge-when-to-worry) - [Why Are My Dog's Eyes Red?](/knowledge/veterinary-medicine/symptom-guides/why-are-my-dogs-eyes-red) - [Why Does My Dog Have Tear Stains? Causes and Fixes](/knowledge/veterinary-medicine/symptom-guides/dog-tear-stains-causes) - [Dog Tear Stains: Causes and Safe Home Remedies](/knowledge/veterinary-medicine/symptom-guides/dog-tear-stains-remedies) - [Why Is My Dog's Eye Watering? Causes and When to Worry](/knowledge/veterinary-medicine/symptom-guides/dog-eye-watering) ## References 1. [Effects of Traditional Chinese Herbal Extracts on Tear Staining, Iron Status, Immune Function, and Antioxidant Capacity in Dogs](https://pubmed.ncbi.nlm.nih.gov/42278031/). Animals : an open access journal from MDPI, 2026. 2. [Disorders of the Nasal Cavity and Tear Ducts in Dogs - Dog Owners](https://www.merckvetmanual.com/dog-owners/eye-disorders-of-dogs/disorders-of-the-nasal-cavity-and-tear-ducts-in-dogs). Merck Veterinary Manual. 3. [Normative values of tear film parameters in brachycephalic dogs using OSA-Vet®: meniscometry and TBUTNI](https://pubmed.ncbi.nlm.nih.gov/41893959/). Veterinary research communications, 2026. 4. [Tear production as measured by Schirmer tear test-1 in dogs with atopic dermatitis](https://pubmed.ncbi.nlm.nih.gov/41030427/). The Canadian veterinary journal = La revue veterinaire canadienne, 2025. 5. [Assessment of meibomian gland morphology and tear-film lipid layer using noncontact infrared meibography and meibometry, respectively, and tear-film osmolarity in healthy dogs](https://pubmed.ncbi.nlm.nih.gov/39528360/). Veterinary ophthalmology, 2026. 6. [Canine Tear Proteomics: A New Frontier in Veterinary Ophthalmology](https://pubmed.ncbi.nlm.nih.gov/42420216/). Veterinary ophthalmology, 2026. 7. [Proteomic Analysis of Tear Film in Dogs and Cats: Emerging Biomarkers of Cognitive Dysfunction and Neurodegenerative Disorders](https://pubmed.ncbi.nlm.nih.gov/41897907/). Animals : an open access journal from MDPI, 2026. ## Further Reading - [Merck Veterinary Manual: Dog Owners](https://www.merckvetmanual.com/dog-owners) - [Cornell Richard P. Riney Canine Health Center: Canine Health Information](https://www.vet.cornell.edu/departments-centers-and-institutes/riney-canine-health-center/canine-health-information) - [American Veterinary Medical Association: Pet Care](https://www.avma.org/resources-tools/pet-owners/petcare)