Item added to your cart
Medically reviewed by Dr. Sarah Collins, DVM
What causes dog tear stains? Dog tear stains form when excess tears overflow onto the fur and oxidize, producing reddish-brown discoloration from compounds called porphyrins. Breed anatomy, narrow tear ducts, minor eye irritation, water mineral content, and diet quality all influence how pronounced staining becomes. A veterinarian should evaluate persistent or worsening staining.
Tear stains are the rust-colored or dark-brown streaks that form on the fur below the inner corner of a dog’s eye. They are not dirt. The discoloration comes from porphyrins — iron-containing molecules produced naturally when the body breaks down red blood cells. Porphyrins are secreted in tears, saliva, and urine. When tear fluid overflows onto the face and sits in the fur, the porphyrins oxidize and stain the coat.
The process is sometimes deepened by yeast (Malassezia spp.) thriving in the warm, damp environment under the eye. Yeast produces its own pigments and enzymes that intensify the reddish-brown color.
Tear staining is most visible on dogs with light or white coats — Maltese, Bichon Frisé, Poodles, Shih Tzus, and similar breeds — but it occurs across all coat colors; it is simply harder to see on dark fur.
Tear staining is almost always the downstream result of excess tear production or tear overflow. Several factors drive this:
Brachycephalic (flat-faced) breeds — Bulldogs, Pugs, Shih Tzus, Boxers — and dogs with prominent, shallow-set eyes tend to have anatomical tear-duct configurations that reduce drainage efficiency. The tears have nowhere to drain properly so they spill over the lower eyelid. This is largely structural and cannot be corrected through diet alone; surgical correction exists for severe cases and should be discussed with a veterinary ophthalmologist.
The nasolacrimal duct normally carries tears from the eye down into the nasal cavity. Partial blockage or narrowing — which can be congenital, inflammatory, or acquired — forces tears to overflow onto the face. A vet can flush tear ducts to rule this out.
Even minor, recurring irritation — fur too close to the eye, dust, environmental particles, or smoke — can stimulate continuous mild tearing. Keeping hair trimmed away from the eye is one of the simplest mechanical interventions.
High-mineral tap water has been associated anecdotally by many veterinarians and breeders with increased tear-stain intensity. The proposed mechanism is that elevated iron and mineral content contributes to higher porphyrin load. Switching to filtered or low-mineral water is a low-risk trial many vets recommend.
Highly processed foods with artificial additives, low-quality proteins, and fillers may influence whole-body inflammatory tone, which in turn can affect tear production in some dogs. This is not a proven direct cause-and-effect relationship, but improving overall diet quality is a reasonable, safe step with benefits beyond tear stain management.
Once the fur is chronically wet from overflow tears, yeast colonizes easily. The yeast colony deepens the brown-red staining and can produce mild odor. Managing the moisture — through regular gentle wiping and keeping the area dry — helps reduce yeast proliferation in the fur.
| Cause | What It Looks Like | Practical Approach | Vet Needed? |
|---|---|---|---|
| Breed anatomy / shallow orbits | Consistent overflow from birth, both eyes | Daily gentle wiping; keep fur trimmed; discuss structural options with vet | Yes, for structural assessment |
| Blocked or narrow tear duct | Overflow usually one eye, possibly worsening | Vet flush of nasolacrimal duct to confirm/rule out obstruction | Yes |
| Fur touching the eye | Squinting or pawing; staining where fur contacts eye | Trim fur away from eye; assess at each groom | If squinting persists, yes |
| High-mineral tap water | Staining intensity correlates with location/water source | Trial switch to filtered or purified water for 4–6 weeks | No, low-risk trial |
| Diet quality | Staining eases when diet improves; may accompany other GI signs | Transition to higher-quality whole-food ingredients; support digestive balance | Discuss with vet if changing diet significantly |
| Yeast in damp fur | Deep rust-brown color, musty odor under eye | Keep area dry; daily gentle wiping; vet-approved wipes if persistent | Yes if odor or skin irritation present |
| Eye infection or corneal issue | Redness, discharge, cloudiness, squinting, pain | Veterinary examination immediately — do not manage at home | Yes — urgent |
The relationship between gut health, diet, and tear staining is a topic of genuine ongoing interest in veterinary nutrition — but it is important to be precise about what the evidence supports.
For dogs with mild, chronic staining where anatomy and infection have been ruled out, many vets suggest a multi-pronged supportive approach: transition to a high-quality whole-food diet with limited artificial additives, switch to filtered water, support digestive balance through a consistent gut-care routine, and maintain daily topical hygiene. To understand how diet and digestive health connect to surface-level signs, our overview of how probiotics may support dogs with skin and allergy concerns covers the gut-to-surface pathway in detail.
For a deeper look at the science behind microbiome support, postbiotics for dogs explains how fermentation-derived compounds influence immune and mucosal health beyond traditional probiotic action.
The following practices are safe, practical, and consistent with what most veterinarians recommend for mild cosmetic tear staining in dogs with no underlying medical condition:
Use a clean, soft cloth dampened with warm water, or a vet-approved canine eye wipe (saline-based, fragrance-free). Wipe outward from the inner corner of the eye. Never rub aggressively — the skin under the eye is delicate. Dry the area after wiping to reduce yeast-friendly moisture.
Hair touching the eye surface is a constant mild irritant. Ask your groomer to keep the periocular fur short, or have a vet show you how to safely trim at home. This single step often reduces tearing significantly in breeds prone to it.
Replace tap water with filtered or purified water and observe over four to six weeks. This is low-cost, low-risk, and worth trialing before more complex interventions.
Review ingredient lists. Artificial dyes, preservatives, and low-quality fillers offer no nutritional benefit and may contribute to whole-body inflammatory load. Moving toward whole-food, high-quality ingredients supports overall health and may reduce staining intensity in susceptible dogs over time.
A consistent gut-care routine that maintains microbiome diversity and mucosal integrity supports the skin and mucous membrane surfaces broadly. Plentum’s Advanced K9 Microbiome Care is formulated as a daily gut-support powder to help maintain digestive balance as part of a complete whole-dog wellness routine.
Cosmetic tear staining in an otherwise healthy dog with confirmed breed anatomy is generally not a medical emergency. However, see your veterinarian if you notice any of the following:
Your vet can perform a Schirmer tear test (measuring tear production), a nasolacrimal flush, fluorescein staining to check for corneal damage, and rule out entropion (inward-rolling eyelid) or distichiasis (extra lashes rubbing the eye). These are not conditions you can diagnose or manage at home.
For a broader picture of how gut health connects to visible signs in your dog, see our guide on 7 symptoms of poor gut health in dogs to watch for — some systemic signs overlap with the same root patterns that may influence tear and skin surface health.
Dog tear stains form when excess tears overflow onto the fur and the iron-containing compounds in those tears (porphyrins) oxidize, producing a reddish-brown discoloration. Breed anatomy is the most common underlying driver, but blocked tear ducts, minor eye irritation, high-mineral water, diet quality, and yeast in damp fur all contribute. A veterinarian should evaluate persistent or worsening staining to rule out medical causes.
The red-brown color comes from porphyrins — natural iron-containing molecules in tears that oxidize when exposed to air and light. When tears pool in the fur instead of draining through the nasolacrimal duct, the porphyrins stain the coat. Yeast colonizing the moist area can deepen the color further. Lighter-coated breeds show this most visibly.
Diet may influence tear stain intensity in some dogs, though it cannot overcome structural anatomy or duct obstruction. High-mineral tap water and processed food ingredients may contribute to porphyrin load. Switching to filtered water and a higher-quality diet is a reasonable, low-risk approach that many veterinarians support as part of overall wellness management.
Safe steps include daily gentle wiping with a clean damp cloth or vet-approved saline eye wipe, keeping fur trimmed away from the eye, switching to filtered water, and improving diet quality. Do not use hydrogen peroxide, human cosmetics, or any product that claims an antibiotic mechanism without a veterinary prescription. If staining is accompanied by redness, pain, or discharge, see a vet before attempting any at-home management.
See a vet promptly if tear staining is new and unexplained, if it affects only one eye, or if you notice eye redness, swelling, cloudiness, squinting, pawing at the eye, unusual discharge, or skin irritation below the eye. These signs can indicate infections, corneal damage, blocked ducts, or structural eyelid problems that require professional diagnosis and treatment.
Support your dog’s everyday gut balance
Plentum Advanced K9 Microbiome Care is a daily gut-support powder formulated to help maintain digestive balance and support your dog’s whole-body wellness routine.
Learn About Advanced K9 Microbiome Care →
Dental Wipes: Work well when you need to clean surfaces quickly, especially with young dogs. They remove debris through motion, yet only do so if someone helps guide them. Cooperation...
Predictable feeding, walk, rest, enrichment, and gut-support routines that help build a calmer, more settled dog day to day.
A vet-informed guide to bathing, shampoo selection, drying, brushing by coat type, ear and paw care, and nutritional skin support for itchy dogs.
How protein quality, essential fatty acids, hydration, and healthy digestion work together to support a shinier, softer dog coat.
