Bidens belongs to the family Asteraceae and is known for its essential oil (EO). They are called by multiple vernacular names, e.g., daisies, blackjacks, and beggarticks depending upon shape and color of the flower. The EO is present in varying amounts in different parts of the plant. Variety of extraction methods have been employed that affect the quality and composition of essential oil. The genus Bidens has been studied for their essential oil around the globe, e.g., North America, China, Hawaii, Kenya, Colombia, Australia, Poland, and Brazil. Essential oils of Bidens are loaded with polyacetylenes, phenolic acids, terpenoids, glycosides, saponins, polysaccharides, and alkaloids. The chemical constituents present in essential oil of Bidens species have unique applications in food, cosmetics and pharmaceutical industry. The chapter explores the essential oil constituents of different Bidens species, their phytochemistry, and potential uses. These chemical constituents may be extracted and used to treat cancer, asthma, anxiety, and other infectious diseases. But due to limited research on its anticancerous potential. There is a need to fully explore the potential of the essential oil in treating cancer and asthma. The details of the essential oil constituents are added separately for each species.