Essential oils (EOs) have attracted considerable scientific interest due to their ecological role in plants and their broad biological applications. This chapter presents an overview of extraction techniques, chemical composition, and biological properties of EOs, with emphasis on (L.) Rendle. Conventional and modern extraction methods are discussed, highlighting factors that influence oil yield and quality. The genus is recognized for its medicinal relevance and high EO content, particularly in monoterpenes such as citronellal, citronellol, and geraniol, which are responsible for diverse biological activities. The chemical profile of oil underpins its applications in pharmaceutical, cosmetic, and agricultural industries. Its biological potential includes antioxidant, antimicrobial, and insecticidal properties, which reinforce its value as a natural alternative to synthetic products. The compilation of studies presented in this chapter demonstrates that EO is a promising candidate for environmentally friendly applications and human health protection.