Phase I Metabolism refers to the initial stage of drug metabolism in the body, where chemical compounds undergo modifications to become more water-soluble. This process primarily involves enzymatic reactions, such as oxidation, reduction, and hydrolysis, which often introduce or expose functional groups on the drug molecules. The main enzymes responsible for Phase I Metabolism are part of the cytochrome P450 family. These enzymes help convert lipophilic substances into more hydrophilic forms, facilitating their excretion from the body. This phase is crucial for detoxifying drugs and other xenobiotics, making them easier to eliminate through urine or bile.