Cat eye discharge: what is normal?

A small amount of brownish or reddish-brown crust in the inner corner of your cat''s eye each morning is completely normal. This is dried tears and eye secretions that accumulate overnight. Gently wipe it away with a damp cotton ball.

What is NOT normal

- Yellow or green discharge: almost always indicates bacterial infection (conjunctivitis). The eye may also appear red, swollen, or partially closed. Common in cats with upper respiratory infections (cat flu).
- Watery, clear discharge from one eye: may indicate a blocked tear duct, a foreign body (like a grass seed), corneal scratch, or early conjunctivitis.
- Thick, white or greyish discharge: chlamydia infection or persistent conjunctivitis.
- Cloudy or bluish cornea: corneal ulcer or injury — urgent.
- One eye bulging or appearing larger: glaucoma or abscess behind the eye — emergency.

Flat-faced (brachycephalic) cats

Persian, British Shorthair, and Exotic Shorthair cats naturally overflow tears (epiphora) due to their shallow eye sockets. This causes brown staining on the face (tear staining). It is not an infection but requires daily cleaning to prevent skin irritation. Your vet may recommend specialised wipes or, in severe cases, surgery.

Upper respiratory infection (cat flu)

The most common cause of eye discharge in cats. Caused by Herpesvirus or Calicivirus, often triggered by stress or another illness. Other signs: sneezing, nasal discharge, and reduced appetite. Herpes recurs throughout life; L-lysine supplementation and reducing stress can reduce flare-ups.

Treatment

Your vet may prescribe antibiotic eye drops (for bacterial conjunctivitis), antiviral treatment (for herpes), or lubricant drops for dry eye (keratoconjunctivitis sicca). Never use human eye drops in cats without veterinary advice.