CYP2C9 (Cytochrome P450 Family 2 Subfamily C Member 9) is an enzyme that plays a vital role in metabolizing many drugs and natural compounds in the body. It assists the liver in detoxifying and eliminating these substances. Variations in the CYP2C9 gene can influence how individuals process medications, affecting drug efficacy and side effects, which is important for personalized medicine and dosing decisions.