Coumarin derivatives have many different types of uses, especially in medicine. These uses include the following: photochemotherapy, anti-HIV and antitumor therapy, central nervous system stimulants, anti inflammatories, anti-coagulants, antibacterials, and dyes. These wide range of uses make coumarin a versatile chemical compound which can be used based on the specific need. Coumarin derivatives prevent vitamin K from functioning as a cofactor in the hepatic synthesis of vitamin K-dependent coagulation factors II, VII, IX, and X. Naturally occurring coumarin derivatives include warfarin, herniarin, psoralen, and imperatorin.