Most people don’t make a habit of checking out their snot after blowing their nose.

But if you’re feeling ill, your mucus could give you a clue about what’s going on.

Nasal mucus helps trap dirt and bacteria and keeps your nasal passages moisturized. Normal mucus is clear to white. When it starts to look yellow or green, it’s because you have a virus, bacterial infection or allergy.

You really can’t tell whether it’s a virus, bacteria or allergy that’s causing the color change. But the color indicates your body is fighting off an intruder.

If your mucus is tinged red or brown, it’s blood (if it’s black, it’s likely dust or dirt). Blood in your mucus could result from frequent nose blowing or breathing very dry air. If you see a lot of blood in your mucus, tell your doctor.

Stuffy sinuses are uncomfortable. And if they’re not cared for, infections can grow in the mucus-clogged nasal passages.

Try these methods to relieve sinus congestion:

  • Run water through your nasal passages. Run water gently into the nasal passages to help clear excess mucus and moisten membranes. Try doing it twice a day. You can also use saline spray during the day.
  • Drink more water. Staying hydrated will help thin out the mucus, making it easier to clear out.
  • Breathe in steam. A steamy shower (or sitting in the bathroom with a hot shower running) will help moisten your nasal passages and make them easier to clear.
  • Get a humidifier. Using a humidifier, especially in the bedroom as you sleep, will help maintain moisture in your nasal passages. Make sure to clean the humidifier regularly.
  • Prop up your head when you sleep. Sleeping propped up on an angle will help prevent mucus from lingering in your sinuses or dripping down your throat.