To understand why your nose plugs up, you first have to understand how tears work. Tears are produced all the time, not just when you cry. Their job is to keep your eyeballs clean and moist. They also protect your eyes from germs. Tears are produced by a lacrimal (LAK-rih-mul) gland above your eye. Openings in this gland carry the tear fluid to the top of your eyeball. When you blink, your eyelid spreads tears over the surface of your eye. Any extra fluid flows to a lacrimal sac near the inner corner of your eye. From there, the fluid drains into your nose. The amount is so small that you usually don’t notice it. When you cry, however, a large amount of tears is produced. The lacrimal sacs can’t drain your tears fast enough. Some of them spill over your eyelids and down your cheeks. The remaining tears flood the sacs and your nose, causing it to “run” or feel plugged up. You can empty these tears by blowing your nose after crying. This also is why sometimes when you have a cold, your eyes “water” or tear, especially when you blow your nose.