D-Lactose monohydrate is widely used in the pharmaceutical industry as an excipient in tablet and capsule formulations. It acts as a filler, binder, and diluent, ensuring proper drug dosage and stability. In the food industry, it serves as a sweetener, texturizer, and bulking agent in products like baked goods, confectionery, and infant formula. It is also utilized in microbiology as a carbon source in culture media for bacterial growth. Additionally, it plays a role in the production of fermented dairy products, enhancing texture and flavor. Its low hygroscopicity makes it suitable for dry powder inhalers in respiratory medications.