The garden vegetable that is a mild, bell-shaped pepper is the bell pepper. Botanically, it is the fruit of Capsicum annuum, although cooks commonly treat it as a vegetable.
Unlike cayenne, serrano and jalapeño peppers, bell peppers are generally non-pungent because they lack capsaicin, the compound responsible for the burning sensation in hot peppers. They register at 0 on the Scoville scale. Their crisp flesh and hollow shape make them popular for salads, stir-fries, roasting and stuffing.
Green, yellow, orange and red bell peppers can come from different cultivars or stages of ripeness. In many varieties, a green pepper is harvested before it fully ripens; the same fruit may become red if left on the plant. Ripening usually brings a sweeter flavor and changes in nutritional content.
The species originated in Mexico, Central America, the Caribbean and northern South America. Bell peppers are also called sweet peppers or capsicums, depending on the region.