Used primarily in microbiology as a selective medium for isolating gram-negative bacteria from clinical or environmental samples. The addition of phenylethyl alcohol inhibits the growth of gram-positive bacteria, making it ideal for promoting the isolation of organisms such as Neisseria and Haemophilus species. It is commonly used in respiratory tract specimen culturing where suppression of normal flora like streptococci is required. Often supplemented with blood or other nutrients to support the growth of fastidious pathogens.