Causes of Cat Eye Discharge and Management

Eye HealthSymptomsMeongsiljang Veterinary Advisory Board

Learn how to assess the urgency of your cat’s eye discharge based on its color and amount, along with cause-specific remedies and home care tips.

When Should You Be Concerned About Cat Eye Discharge?

A cat with a small amount of clear discharge around the eyes

A small amount of clear, slightly sticky discharge around your cat’s eyes in the morning is normal. Just as people may have eye crust after sleeping, cats can develop a little discharge as their tears dry. However, if the discharge turns yellow or green, or if there’s a noticeable increase in amount, it could signal an infection or another underlying condition. By carefully observing the color and quantity of the discharge, along with any accompanying symptoms, you can determine when it’s time to visit the vet.

Urgency Assessment Table by Discharge Color

Please check your cat’s eye discharge against the table below.

Discharge Color	Meaning	Urgency
Clear/Transparent	Normal tear secretion	Monitor
White/Gray	Possible mild irritation	Monitor for 1–2 days
Yellow	Suspected bacterial infection	Visit a clinic within 2–3 days
Green	High likelihood of bacterial infection	Seek prompt veterinary care
Red/Brown	Tear staining or bleeding	Veterinary evaluation required

Watch Out If These Symptoms Appear Alongside

Eye discharge rarely occurs on its own. If you notice any of the following symptoms alongside it, an underlying condition may be present.

Redness of the eyes: Inflammation of the conjunctiva causes the white part of the eye to turn red and increases eye discharge.

Conjunctival swelling: This refers to swelling of the conjunctiva and is commonly seen in the early stages of viral or bacterial infections.

Squinting: If your pet keeps squinting with one eye, it may indicate a corneal injury.

Sneezing and nasal discharge: Frequent sneezing along with eye discharge suggests a possible upper respiratory tract infection.

Cases Requiring Immediate Veterinary Care

If your kitten can’t fully open its eyes, has greenish eye discharge accompanied by a fever, or if the surface of the cornea appears cloudy, seek veterinary care immediately. Upper respiratory infections can progress rapidly in young kittens, potentially causing severe eye damage. Waiting a day or two to see if symptoms improve can be dangerous.

Infectious Causes: Viruses and Bacteria

The most common infectious cause of feline eye discharge is feline herpesvirus type 1 (FHV-1). According to veterinary textbooks, herpesvirus conjunctivitis initially presents with clear, serous tearing from both eyes, which progresses to mucopurulent discharge over time. Secondary bacterial infections can exacerbate the condition, leading to more severe purulent discharge. Characteristic signs include conjunctival swelling (chemosis) and conjunctivitis. Other common causes of infectious conjunctivitis in cats include Chlamydophila felis, Mycoplasma, feline calicivirus (FCV), and Bordetella. Chlamydial infection causes unilateral or bilateral conjunctivitis and conjunctival swelling, with relatively mild respiratory symptoms. Because feline calicivirus frequently causes oral ulcers, it should be strongly suspected when conjunctival signs appear alongside mouth ulcers. When secondary bacterial infection occurs, there is an increase in thick, yellow or green discharge, which is particularly common in kittens and immunocompromised cats.

Non-infectious Causes: Irritation and Structural Issues

Excessive eye discharge can occur even without an infection.

Foreign body irritation: When dust, sand, or cat litter particles get into the eyes, they can increase tear production and eye discharge.

Allergies: Reactions to allergens such as pollen, air fresheners, or detergents can cause excessive clear tearing.

Blocked tear ducts: If the passage that drains tears into the nose is narrow or blocked, tears may overflow and appear as eye discharge. This is common in brachycephalic breeds like Persians and Himalayans.

Eyelash abnormalities: If eyelashes grow inward and irritate the cornea, it can lead to chronic eye discharge.

Persian cat with tear stains around the eyes

Diagnosis and Treatment at the Veterinary Clinic

Your veterinarian will examine the color and amount of eye discharge, along with any accompanying symptoms, before proceeding with necessary tests.

Fluorescein staining test: A basic test to check for corneal injuries.

Tear production test: Measures whether sufficient tears are being produced.

Bacterial culture test: Identifies the causative bacteria when infection is suspected.

Treatment varies depending on the underlying cause. If a bacterial infection is present, antibiotic eye drops will be prescribed. Appropriate treatment based on your veterinarian’s diagnosis is also necessary for viral infections or other causes. In cases of allergies or irritants, environmental management to avoid the triggering substance, along with veterinarian-prescribed eye drops, may be recommended.

Feline Herpesvirus Is Difficult to Cure Completely

Feline herpesvirus remains latent in the body after initial infection. It can reactivate during periods of stress or when the immune system is compromised, leading to recurrent symptoms such as ocular discharge, conjunctivitis, and sneezing. Since a complete cure is not possible, managing recurrences is key, and it’s best to work with your veterinarian to develop a long-term care plan.

How to Manage Eye Discharge at Home

Light eye discharge can be managed consistently at home.

Use clean gauze: When wiping away eye discharge, use clean gauze or a soft cotton pad. Avoid using tissues, as their fibers can get into the eyes.

Soften with lukewarm water: Do not forcefully remove hardened eye discharge. Instead, gently soften it by applying gauze soaked in lukewarm water.

Use a separate pad for each eye: To prevent infection, do not use the same gauze or pad on both eyes.

Check the living environment: Use low-dust cat litter and ensure regular indoor ventilation.

A caregiver gently wiping a cat’s eye discharge with gauze

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently Asked Questions

My cat only has eye discharge in one eye. Is this normal?

If discharge is present in only one eye, it could indicate a foreign object or a corneal injury in that eye. If the condition persists for more than two to three days, it is advisable to have it checked at a veterinary clinic.

My kitten’s eyes are stuck shut with crust. What should I do?

Gently soften and remove the discharge with a clean gauze pad moistened with lukewarm water. If this needs to be done multiple times a day or if yellow discharge persists, it may indicate an infection, so please visit a veterinary clinic promptly.

The eye discharge is brown. Is it blood?

Brown eye discharge is usually caused by components in tears oxidizing when exposed to air. Blood-tinged discharge, which appears more pinkish-red, is rare. However, if you notice an increase in brown discharge or a foul odor, please have your pet checked at a veterinary clinic.

Can I use human artificial tears for my cat?

Human artificial tears may contain ingredients that are unsuitable for cats. In particular, products containing preservatives can cause irritation, so be sure to use veterinary-approved products under the guidance of your veterinarian.

What can I do on a daily basis to help prevent eye discharge in my cat?

Feline herpesvirus can reactivate during periods of stress or when the immune system is compromised, so maintaining a stable living environment and managing stress are paramount. Use low-dust cat litter and ensure regular indoor ventilation. Gently wiping the area around your cat’s eyes with clean gauze two to three times a week can also be helpful, and we recommend regular veterinary check-ups to monitor eye health.