α1-Antichymotrypsin, derived from human plasma, is primarily used in medical and research applications due to its role as a serine protease inhibitor. It is particularly significant in regulating inflammation and tissue remodeling by inhibiting enzymes like chymotrypsin and cathepsin G. In clinical settings, it is utilized to study conditions associated with protease imbalance, such as chronic inflammatory diseases, Alzheimer's disease, and certain cancers. Additionally, it serves as a biomarker in diagnosing and monitoring disease progression. In research, it is employed to understand protease-related pathways and develop therapeutic strategies targeting protease activity. Its application also extends to biotechnological processes where protease inhibition is required for protein stability and function.