Chilli shrubs are perennial and short-lived. They can grow up to 1.5 m in height. Their stems are woody at the base, fleshy and either erect or semi-prostrate. The shrub consists of the main taproot with many lateral roots. The leaves can grow up to 12 cm long and 7.5 cm wide and are unequal in shape with a pointed tip. Chilli flowers occur singly or in small groups of two to three flowers. They are small and bisexual with have five to six petals each. Flowers of Capsicum annum are white-green, while those of Capsicum frutescent are yellow or white-green.
The chili fruit is hollow with many seeds. They are found in different colours like green, orange, white, yellow and red.
Pungency varies in different varieties. Red chilies get their colour from a colouring compound called capsanthin and have a hot, pungent taste due to a chemical called capsaicin. The numerous small chili seeds also contain capsaicin.