The chili pepper (also chile pepper, chilli pepper, or simply chilli) from Nahuatl chīlli Nahuatl pronunciation (About this sound listen)) is the fruit of plants from the genus Capsicum, members of the nightshade family, Solanaceae. They are widely used in many cuisines to add spiciness to dishes. The substances that give chili peppers their intensity when ingested or applied topically are capsaicin and related compounds known as capsaicinoids.