Cat tearing, eyes look a bit red.

A small amount of eye discharge is normal and usually diet-related – oily cat food easily causes heat, leading to lots of eye gunk and eventually red tear stains. If the cat has heavy discharge every day, that is not normal; wipe it clean daily and switch to a light, easily digestible diet with more water.

Eye diseases such as keratitis, conjunctivitis, corneal ulcers, or entropion also cause excess discharge, and treatment must target the specific cause.