Used in microbiology to differentiate enteric bacteria based on their ability to ferment carbohydrates and produce hydrogen sulfide. It helps identify organisms like Salmonella and Shigella by observing color changes in the medium. The agar allows simultaneous testing of glucose and lactose fermentation. A red slant and yellow butt indicates glucose fermentation only, while a yellow slant and yellow butt suggests lactose fermentation. Production of hydrogen sulfide is detected by the formation of black precipitate. Commonly used in clinical labs for stool sample analysis and in food and water testing to isolate and characterize intestinal pathogens.