Capsaicin is an active component of chili pepper plants that belongs to the genus capsicum. It works as a chemical irritant for mammals, including human beings. It creates a sensation of burning in the tissue with which it comes into contact. Capsaicin and associated alkaloids combine to form capsaicinoids, which are generated as secondary metabolites by chili peppers. They may work as deterrents against some specific mammals and fungi. Pure capsaicin is highly pungent, colorless, hydrophobic and crystalline to waxy solid compound. It is utilized for several purposes, such as an analgesic in topical ointments and dermal patches to relieve pain. It works as an effective medicine for lessening the signs of peripheral neuropathy like post-herpetic neuralgia. This book is a compilation of chapters that discuss the most vital concepts and emerging trends in the study of capsaicin. It includes contributions of experts and scientists which will provide innovative insights on the physiology and pharmacology of capsaicin.