Used in microbiology to isolate and differentiate enteric pathogens, particularly Salmonella and Shigella species, from clinical samples such as stool. It supports the growth of Gram-negative bacteria while inhibiting Gram-positive organisms due to bile salts and sodium deoxycholate. The medium contains lactose, sucrose, and salicin, along with pH indicators that help distinguish fermenters from non-fermenters based on colony color. Lactose non-fermenting colonies like Salmonella and Shigella appear green or blue-green, often with black centers due to hydrogen sulfide production, while fermenters such as Escherichia coli produce orange to salmon-colored colonies. This makes Hektoen Enteric Agar valuable in diagnostic laboratories for screening gastrointestinal infections.