---
title: "Cat Eye Discharge"
description: "Watery eyes in flat-faced cats differ from thick yellow discharge of infection. Squinting or cloudiness needs urgent care — corneal ulcers are painful."
url: "https://pethealth.org.uk/health/cat-eye-discharge"
canonical: "https://pethealth.org.uk/health/cat-eye-discharge"
date_published: "2026-06-25"
date_modified: "2026-06-25"
source: "PETHEALTH+"
---

# Cat Eye Discharge

**Small amounts of clear discharge** may be normal in flat-faced breeds or after sleep. **Thick yellow or green discharge, squinting, redness, or cloudiness** needs a vet — often cat flu, infection, or a corneal ulcer. Eye problems in cats can progress quickly and should not wait.

## Normal discharge vs illness

A trace of clear moisture or light crusting after sleep is common. Persians and other flat-faced breeds often have **tear staining** from blocked tear ducts — this is cosmetic unless the eye looks sore.

**Usually harmless:**

- Clear discharge without squinting or redness
- Light sleep crusting that wipes away easily
- Tear staining in Persians without pain signs

**Needs investigation:**

- **Yellow, green, or bloody** discharge
- **Squinting** or keeping the eye closed
- **Red or swollen** eyelids
- **Cloudy or scratched** cornea
- Discharge with [sneezing](/health/cat-sneezing-causes) or [fast breathing](/health/cat-breathing-fast)

## Common causes in UK cats

| Cause | Typical signs | Notes |
|-------|---------------|-------|
| **Cat flu (URI)** | Watery then thick discharge, sneezing | Herpesvirus and calicivirus — see [Respiratory infection](/health/cat-respiratory-infection-uk) |
| **Bacterial conjunctivitis** | Yellow-green pus, red eye | Often secondary to viral infection |
| **Blocked tear ducts** | Constant wetness, tear staining | Common in Persians |
| **Corneal ulcer** | Squinting, watery or cloudy eye | Painful — same-day vet care |
| **Allergies and irritants** | Clear discharge, rubbing face | Smoke, dust, perfumed litter |
| **Foreign body** | Sudden squinting | Dust, hair, or grass under eyelid |
| **Glaucoma** | Red, painful, enlarged eye | Emergency — vision at risk |

### Infectious causes

**Cat flu** is a common cause of conjunctivitis in the UK, especially in kittens and unvaccinated cats. Discharge may start watery and become thick. [Sneezing](/health/cat-sneezing-causes), mouth ulcers, and fever can accompany eye signs. Vaccination reduces severity but does not eliminate all viruses.

## When to see a vet urgently

Phone your vet **the same day** or use **emergency out-of-hours care** if:

- Your cat is **squinting** or will not open the eye
- The eye looks **cloudy, blue, or scratched**
- **Thick green or yellow** discharge with lethargy
- **Bulging or very swollen** eye
- Discharge with **open-mouth breathing** — see [Cat breathing fast](/health/cat-breathing-fast)
- **Kitten** with sealed-shut eyes or heavy discharge

Book a **routine appointment within a few days** for mild discharge that persists more than 48 hours without squinting.

## Home care before your appointment

While waiting for a vet visit, note:

- **Which eye** is affected — photograph discharge if safe
- **Vaccination status** and contact with other cats
- **Other symptoms** — [sneezing](/health/cat-sneezing-causes), [not eating](/health/cat-not-eating), or [drooling](/health/cat-drooling-excessively)
- **When** symptoms started and whether they are worsening

**What you can do at home:**

- Gently wipe discharge with **cooled boiled water** — one cloth per eye
- Wipe from the **inner corner outward**
- Prevent **pawing at the eye** — a cone if advised
- **Isolate** from other cats if cat flu is suspected

**What not to do:**

- Do not use **human eye drops** without vet advice
- Do not share cloths between cats if infection is suspected
- Do not delay if your cat is **squinting**

## What your vet may do

Examination may include corneal staining, checking tear production, and assessing for ulcers. Your vet might recommend:

- **Antibiotic or antiviral drops** for infection or cat flu
- **L-lysine or supportive care** for recurrent herpesvirus flare-ups
- **Foreign body removal** if needed
- **Referral** for glaucoma, deep ulcers, or surgery

Treatment depends on cause — ulcers need prompt care; chronic cat flu may need long-term management. See [Cat dental care UK](/health/cat-dental-care-uk) if oral health contributes to overall wellbeing.

## Related guides

- [Cat sneezing causes](/health/cat-sneezing-causes)
- [Cat breathing fast](/health/cat-breathing-fast)
- [Cat respiratory infection UK](/health/cat-respiratory-infection-uk)
- [Cat not eating](/health/cat-not-eating)
- [Cat dental care UK](/health/cat-dental-care-uk)

## FAQs

### Is cat eye discharge contagious?

Viral cat flu can spread between cats in the same household. Isolate new cases if possible and wash hands after handling. Discharge from blocked tear ducts alone is not contagious.

### Can allergies cause runny eyes in cats?

Yes — dust, pollen, and smoke can irritate eyes. Allergies usually cause clear discharge without squinting, but persistent signs still deserve a vet check.

### When is eye discharge urgent in cats?

Squinting, a bulging eye, thick green pus, or a cloudy cornea needs same-day care. Corneal ulcers are painful and can worsen within hours.

### Do kittens get eye infections?

Yes — neonatal conjunctivitis is common without early vet care, especially in kittens from feral or multi-cat backgrounds. Prompt treatment protects vision.

## Sources

- [PDSA — Cat health advice](https://www.pdsa.org.uk/pet-help-and-advice/pet-health-hub)
- [Blue Cross — Cat advice](https://www.bluecross.org.uk/pet-advice)
- [Cats Protection — Health advice](https://www.cats.org.uk/help-and-advice)

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Last modified: 2026-06-25