Snot, also known as nasal mucus, is produced by glands and specialized cells lining the inside of your nose and throat. These glands include goblet cells and submucosal glands, which secrete mucus composed mostly of water and mucin, a gel-forming protein

. The mucus membranes in your nose and sinuses produce about 1 to 2 quarts (roughly 1 to 2 liters) of mucus daily, which helps keep the nasal passages moist, traps dust, germs, and other particles, and fights infections

. The mucus is sticky, trapping harmful particles like dust, pollen, and pathogens to prevent them from entering your body. Tiny hair-like structures called cilia move the mucus toward your throat, where you usually swallow it without noticing

. When you have a cold or an infection, your body produces extra mucus to trap and expel more germs, which is why you get a runny nose or more visible snot

. In summary, snot comes from mucus-producing glands and cells in your nasal passages and throat, serving as a protective and moisturizing barrier for your respiratory system