CAPSAICINOIDS

               The spiciness of chillies is due to the presence of compounds called capsaicinoids.The two compounds above are the main capsaicinoids in chilli peppers. They cause a burning sensation when they come into contact with mucous membranes,due to their interaction with pain and heat sensing neurons.
            Capsaicin is also used in some brands of pepper spray,and studies have shown it may be capable of killing prostate and lung cancer cells.It is toxic in large quantities.