Maintaining physical and mental well-being is essential to enhancing the quality of life. Essential oils (EOs) have been used for centuries in different cultures, serving as therapeutic, cosmetic, aromatic and even spiritual agents. EOs are extracted from various parts of the plant, such as leaves, flowers, barks and fruits, using methods such as steam and hydrodistillation. The main chemical components of volatile oils are classified into terpenes and phenylpropanoids. They are considered resourceful, possessing various pharmacological and psychological properties, including antibacterial, antiviral, antioxidant, anti-inflammatory, immunity-boosting, calming and memory- and alertness-improving effects. This chapter discusses the potential impact of essential oils on physical and mental well-being, focusing on mechanisms and their chemistry. The chapter also provides insight into their use in clinical and pre-clinical trials. In addition, safety precautions are also covered. The data are collected from databases such as PubMed, Google Scholar, Scopus, Science Direct and Web of Science.