They're fruit, actually, by botanical standards.
All chilies are members of the capsicum family, which includes both sweet and hot varieties.
Capsaicin is the substance found in chilies that gives them their fiery kick, and while a hot pepper's most memorable characteristic may be its spiciness, they all vary greatly in both heat and flavor. Too hot to handle Like many foods throughout history, chili peppers have been used as often for their health-promoting properties as they have been a flavoring. One of the most useful traits of the chili is its ability to induce perspiration. If you've ever eaten food that was spicy enough to cause a damp brow you understand this completely. It's no coincidence, then, that chilies are ubiquitous in the cuisines that are close to the equator.