Used in microbiology to detect hydrogen sulfide (H₂S) production by bacteria, especially in the identification of enteric pathogens such as Salmonella and Shigella. The medium allows for the differentiation of H₂S-producing organisms based on the formation of black colonies or black precipitates due to the reaction between H₂S and iron salts in the agar. Commonly used in clinical labs for stool culture and in food and water testing to isolate and identify pathogenic bacteria. Its visual results make it a simple and effective tool in preliminary bacterial screening.