That yellow stuff you find in the corners of your eyes after waking up is often called “sleep” or “eye discharge.” It’s actually a natural mixture of mucus, oils, dead skin cells, and dead bacteria. Your eyes produce mucus and oils to stay moist, but because you don’t blink while sleeping, this buildup collects in the corners overnight.

The yellowish tint comes mostly from the dead bacteria your eyes fought off while you were asleep. It’s a sign your body is working hard to protect your eyes and keep them healthy. Think of it like a tiny battle your immune system fights during the night to clear away any harmful invaders.

However, while some discharge is normal, if it becomes excessive or comes with redness, itching, or burning, it might mean you have an infection, such as conjunctivitis or pink eye. In these cases, it’s important to seek medical advice to prevent the condition from worsening.

So next time you notice that yellow goop, remember it’s just your body’s way of cleaning your eyes and keeping them safe—an everyday, behind-the-scenes miracle happening while you rest.