Question of the Day: Do bell peppers have capsaicin?
Quick Answer: No, bell peppers do not have capsaicin.
Capsaicin is the chemical compound that peppers produce to deter animals from eating them. It is also what gives chilies their fire. The more capsaicin a pepper contains, the hotter it will be.
Bell peppers are incapable of producing capsaicin, and that is why people often refer to bell peppers as sweet peppers. They completely lack heat.