Why color helps but is not a diagnosis
The color and texture of eye discharge can give useful clues, and they are worth describing to your vet. But color cannot reliably tell you the cause. Different conditions can produce similar discharge, and one condition can change over time. Use this guide to judge how closely to watch your cat and how soon to call, not to diagnose or treat at home.
Also note the amount, whether it affects one or both eyes, and any other signs such as squinting, redness, sneezing, or changes in appetite. A photo taken in good light can help your vet.
Clear and watery discharge
Clear, watery discharge is the mildest-looking type. It can come from irritants, allergies, early viral infections, or tear drainage problems. If your cat is bright and eating normally and the eye looks comfortable, a short period of watching may be reasonable, but contact your vet if it continues beyond a day or two or is joined by other signs. Our guide to a cat runny eye goes into causes in more detail.
White or gray mucus
Mucus-like, stringy, or cloudy white-gray discharge can accompany irritation or inflammation of the eye surface. It can also be linked to dry eye, where the eye does not produce enough tears. Because this needs a proper exam to sort out, it is a reason to book a vet appointment rather than wait for it to clear.
Yellow or green discharge
Thick yellow or green discharge usually suggests an infection and inflammation are involved. It may be accompanied by redness, squinting, and sometimes sneezing or nasal discharge. Cats with this kind of discharge generally need to be seen by a vet, as prescription treatment is often needed. Do not use leftover or human eye products.
Reddish-brown crust and “eye boogers”
Many cats, especially light-coated or flat-faced ones, develop brown or reddish-brown staining and dried crusts at the inner corner of the eyes. This often reflects tears that dry on the face and darken over time. A small amount that is stable and not causing discomfort is commonly seen.
However, a sudden increase, a wet eye, or crusting with redness or squinting should be examined. Brown staining can also accompany tear drainage problems that a vet can assess. To remove dried crust, a clean cotton pad moistened with warm water can be used around the eye, not on it.
Red or bloody discharge
Discharge that looks red or blood-tinged is different from dried brown staining. It can result from irritation, injury, or inflammation, and sometimes from more serious problems inside the eye. This should be checked by a vet promptly, and urgently if you see blood within the eye itself, marked swelling, or if your cat is in obvious pain.
What is conjunctivitis in cats?
Conjunctivitis is inflammation of the conjunctiva, the thin membrane lining the eyelids and covering the white of the eye. It causes redness and often discharge that can range from watery to thick and colored. In cats it is commonly linked to viral infections such as feline herpesvirus (also behind the cat cold), bacterial infections, or irritants and allergies. Read more in pink around cat eyes: conjunctivitis and more.
A sore eye: other signs to watch
A painful eye often shows as squinting, holding the eye closed, light sensitivity, pawing at the face, or a third eyelid partly covering the eye. Cloudiness or a change in pupil size also deserves quick attention. Sore eyes can involve a scratch or ulcer, which may worsen without treatment.
When to see a vet
Book a prompt appointment if discharge is yellow, green, bloody, or thick, if it lasts more than a day or two, or if it affects both eyes along with sneezing. Seek urgent care if the eye is closed, cloudy, bulging, bleeding, or your cat seems to be in pain. Kittens and senior cats should be seen sooner rather than later.
Quick reference
| Appearance | Possible meaning | Suggested action |
|---|---|---|
| Clear, watery | Irritant, allergy, early infection, drainage issue | Watch closely; vet if beyond a day or two or other signs |
| White or gray mucus | Surface irritation or dry eye | Vet appointment |
| Yellow or green | Likely infection or inflammation | Vet visit soon |
| Reddish-brown crust | Dried tears, drainage issue | Monitor; vet if changing or with redness |
| Red or bloody | Irritation, injury, or deeper problem | Prompt vet visit; urgent if severe |