**1. Introduction**

*Capsicum* is one of the most important genera in the Solanaceae family and consists of almost 30 species [1]. Their fruits were commonly referred to as peppers or chili peppers, having a bell shape that appears in different colors such as red, green, orange, and yellow. These have been commonly used in their diet by human society from ancient times as herb and spice. *Capsicum* is widely used as an essential ingredient in kitchens worldwide for their pungent flavor and scent and to prevent food contamination. It is known under many names, such as red pepper, chili pepper, paprika, tabasco, aji, cayenne, and tabasco jalapeno, because of its global consumption [2]. The genus *Capsicum* is comprised of various numbers of wild and few domestic species. The species domesticated are *Capsicum annum, C. baccalaureus, C. honey, C. frutescens, C. pudders,* in which *C. chinense* is the fruit with the highest pungency [3]. *Capsicum* has been documented for its wide range of activities, such as pain killers, cardiovascular protection, a cancer chemopreventive, and antioxidant effects. This chapter provides a comprehensive description of the capsaicin and its analogs as well as, more specifically, look into its therapeutic potential in various human cancer and future therapeutic directions of capsaicin.
