A potent compound that gives some chiles their fiery nature. Most of the capsaicin (up to 80 percent) is found in the seeds and membranes of a chile. Since neither cooking nor freezing diminishes capsaicin's intensity, removing a chile's seeds and veins is the only way to reduce its heat. The caustic oils found in chiles cause an intense burning sensation, which can severely irritate skin and eyes. Capsaicin is known for its decongestant qualities. It also causes the brain to produce endorphins, which promote a sense of well-being.