The chili pepper is the fruit of plants from the genus Capsicum, members of the nightshade family, Solanaceae. In Britain, Australia, Ireland, New Zealand, South Africa, Pakistan, India, and other Asian countries, it is usually known simply as the chilli.
The substances that give chili peppers their intensity when ingested or applied topically are capsaicin and several related chemicals, collectively called capsaicinoids.
Chili peppers originated in the Americas. After the Columbian Exchange, many cultivars of chili pepper spread across the world, used in both food and medicine. Chilies were brought to Asia by Portuguese navigators during the 16th century. (source : wikipedia)