The chili pepper (also chile, chile pepper, chilli pepper, or chilli), from Nahuatl chīlli , is the fruit of plants from the genus Capsicum which are members of the nightshade family, Solanaceae. Chili peppers are widely used in many cuisines as a spice to add heat to dishes. The substances that give chili peppers their intensity when ingested or applied topically are capsaicin and related compounds known as capsaicinoids.