Chilli or cayenne pepper (Capsicum annuum). It is native of
central and South America. Cayenne is derived from Greek 
word meaning ‘to bite’. The Latin name capsicum refers to its 
hot and pungent taste. The South American natives believed 
that eating six cayenne peppers daily for eight days make them 
excellent blow-gunners. One of its common names, Tabasco
sauce, derives from the Mexican state of Tabasco. There is even
a Tabasco flavoured ice cream in Mexico. While used mainly to 
spice up foods, the active constituent capsaicin that produces 
the heat sensation is used as a counter irritant in the treatment 
of post-herpetic neuralgia. Capsaicin depletes substance P 
which is an important neurotransmitters of peripheral pain 
impulses from the small sensory peripheral and prevents its 
reaccumulation. Capsaicin is also used in the manufacturing 
of self-defence tear-gas sprays.