Spicy food can make your nose run because of a chemical compound that irritates your mucus membranes.

This chemical compound is called capsaicin, and it is found in such foods as hot peppers. It is a strong irritant that can irritate both the mucus membranes of the nose and the tear ducts of a person's eyes. This is why oftentimes your nose can run and your eyes water while enjoying a spicy meal. Capsaicin can also dilate blood vessels, which is why people also tend to turn red in the face!