Look, it's not gross at all to take a peek inside your tissue after blowing your nose or sneezing. You never really know what's going to come out of your nose, especially if you have allergies. And experts say you can tell a lot about your health by examining your mucus. However, the idea that you can diagnose a cold or virus just by looking at your snot is actually a myth.
Your body is constantly making mucus, about one liter or more of the slimy stuff a day, says Neil L. Kao, MD, FAAAAI, an allergist in Greenville, SC. Normal mucus is made up of mostly water, with some proteins mixed in there that give it its texture, he says. These proteins and other substances that get stuck in your mucus can also change its color.
When you have a cold, your mucus might change color, but "mucus from an infection can look like just about anything," says Derrick R. Ward, MD, an allergist in Kansas City, "There's no way to differentiate between a viral or bacteria infection based on mucus color." Instead of focusing solely on the shade of your boogers, it's more worthwhile to pay attention to the amount of mucus you're making as well as any other symptoms of a cold, such as a headache or a sore throat, if you're trying to tell if you're sick.
That said, given the range of colors that your snot can be, ahead are some ones to look out for next time you reach for a tissue.