Cayenne pepper is a hot, red chili pepper used fresh or dried and ground as a spice to add fiery heat to a wide variety of dishes, from savory meals like chili, stews, and curries to sweet treats like hot chocolate, and is a staple in cuisines worldwide, including Cajun, Mexican, and Indian. It's known for its spicy kick, which comes from capsaicin, and is used sparingly, often starting with just a pinch, to avoid overpowering other flavors.