Birch has always been a little more expressive than most dogs I’ve known. But when I noticed his eyes were consistently wet — not just after a muddy walk or a good nap, but all the time — I started paying closer attention. It took me longer than it should have to understand that chronic tear overflow isn’t just a quirk. It’s a symptom.
Watery eyes in dogs have an actual medical term: epiphora. It refers to the overflow of tears onto the face, which can be normal in small amounts but becomes a flag when it’s excessive, chronic, or accompanied by other changes. Here’s what I’ve learned about what drives it, when it matters, and what to do about it.
Why Do Dogs’ Eyes Water?
A healthy dog’s eye produces tears continuously to lubricate, protect, and clean the surface. Normally those tears drain through tiny ducts at the inner corner of the eye into the nasal passage. Epiphora happens when this drainage system gets overwhelmed or blocked, and excess tears spill down the face instead.
The triggers are varied:
- Blocked or narrowed tear ducts — one of the most common structural causes, especially in brachycephalic breeds (Bulldogs, Pugs, Shih Tzus, Boxers)
- Allergies — environmental allergens can trigger increased tear production, just like in humans
- Eye irritation or foreign body — a hair, dust, or tiny debris in the eye
- Entropion — a condition where the eyelid rolls inward, causing lashes to rub against the eye surface
- Distichiasis — extra eyelashes growing from abnormal locations and contacting the eye
- Eye infections — bacterial or viral
- Corneal ulcer or injury
- Glaucoma or other pressure issues
- Dental disease — tooth root infections near the eye can cause drainage symptoms
That last one surprised me when I learned it. An infected upper tooth root (particularly the carnassial tooth) sits close enough to the tear duct and nasal area that it can cause or worsen epiphora. This is one more reason regular dental care matters more than most people realize.
The Staining Problem
You’ve probably seen the reddish-brown “tear stains” that appear below the eyes of light-colored dogs — common in Maltese, Bichons, Poodles, and similar breeds. This discoloration is caused by a pigment called porphyrin, present in tears (and saliva and urine). When tears overflow chronically onto the fur, porphyrin oxidizes and leaves those characteristic rusty stains.
Tear staining itself is cosmetic. The issue is what’s driving it. Persistent tear overflow creates a chronically moist environment under the eye that becomes a breeding ground for bacterial and yeast overgrowth. That’s when you start to see odor, redness, skin irritation, and sometimes infection in the skin fold.
If you have a light-coated dog with chronic tear staining, the goal isn’t just treating the stains — it’s figuring out why the overflow is happening and addressing the root cause.
When to See a Vet
Some baseline wateriness is normal. What warrants a vet call:
- Discharge that’s yellow, green, or thick/mucoid rather than clear
- Redness of the white of the eye or the tissue around the eye
- Cloudiness of the cornea
- Your dog squinting, pawing at the eye, or holding it partially closed
- Sudden increase in tearing, especially in one eye only
- Any eye swelling
- Chronic tearing that’s been present for weeks or months without evaluation
Anything that suggests pain — squinting, pawing, rubbing the face on the carpet — should be seen the same day if possible. Eye issues can progress quickly, and a corneal ulcer that’s 24 hours old is much easier to treat than one that’s been rubbed and infected for a week.
What Diagnosis Looks Like
When I finally brought Birch in for his watery eyes, our vet did a thorough exam that included specific tests. She used a fluorescein stain (a safe orange dye that shows up under a blue light) to check for corneal scratches or ulcers. She also did a Schirmer tear test to measure his tear production — because both too many tears and too few can cause similar surface-level symptoms. And she checked whether his nasolacrimal ducts were patent by flushing them.
Birch’s diagnosis was mild allergic conjunctivitis, likely seasonal. We started him on a low-dose antihistamine (confirmed safe for dogs with our vet — please don’t dose OTC antihistamines without vet guidance on type and amount), and I committed to more consistent eye maintenance at home.
Home Management
For dogs with chronic low-grade epiphora that’s been evaluated and has a known benign cause, consistent home care makes a significant difference:
Daily gentle cleaning: Use a soft cloth dampened with sterile saline or a veterinary eye wash to gently wipe away any discharge or crust. Vetericyn Plus Eye Wash is what I keep on Birch’s shelf — it’s gentle enough for daily use and specifically formulated for dog eyes.
Keeping the fur trimmed: If fur near the eye is long enough to contact the surface, it causes constant irritation. Regular trimming around the eye area reduces this dramatically.
Checking food ingredients: Some dogs’ tear production worsens with certain food additives, dyes, or ingredients. If your dog’s tear overflow is chronic and you’ve ruled out structural issues, an elimination trial with a limited-ingredient diet is worth discussing with your vet. Hill’s Science Diet Sensitive Stomach and Skin is one option that’s vet-recommended for dogs whose symptoms may have a dietary component.
The Senior Dog Note
If your dog is older and developing increasing tear overflow for the first time, it warrants closer evaluation than in a younger dog. Changes in eye health are common in senior dogs — corneal changes, early cataract formation, increased intraocular pressure — and the eye is one of the first places systemic health changes show up. An annual eye exam as part of your senior dog’s wellness workup is genuinely worth adding if your vet doesn’t already do one routinely.
Birch’s eyes have been much more stable since we addressed the allergy piece. I still wipe them every morning, still check them during our weekly once-over. Eyes are one of those things where early attention saves a lot of grief later. Don’t let “it’s just watery eyes” become something bigger because it was easy to ignore.
Have questions about what you’re seeing in your dog’s eyes? Leave them in the comments — happy to share what I’ve learned.