The olfaction is not a degraded sense, but it plays an important function not only in survival but also in human senses, emotions, memories, and social functions. It is a complex and difficult characteristic of the olfaction that has only recently been scientific development. Although interest has increased recently, the characteristics and functions of human olfactory function are not well known, and medical research are also focused on disease. In fact, interest in medical aspects such as the cause of olfactory diseases, olfactory function tests, treatments, and olfactory rehabilitation has only recently grown, and other odors, olfactory characteristics, functions, and humanities have little interest. Therefore, beyond the medical perspective on human olfaction and smell, we intend to increase our understanding and interest in the olfaction, which has been underestimated in importance, through humanistic considerations. The olfaction is also a sense of a person, and its value should be paid attention again. It’s never an inferior sense. Understanding the functions of the underrated human olfaction and re-discovering the lost olfaction and smell culture will enrich life.