Eosin methylene blue medium is a selective medium, and Eosin methylene blue can inhibit the growth of Escherichia coli. Escherichia coli can't use eosin methylene blue as carbon source. In the culture medium, Escherichia coli will form colonies, which will be separated and identified. Selective inhibition helps to isolate Escherichia coli in laboratory or clinical diagnosis for further research and detection.