Endo agar (also called Endo's medium) is a microbiological growth medium with a faint pink colour.[1] Originally developed for the isolation of Salmonella typhi, it is now used mostly as a coliform medium. Most gram-negative organisms grow well in this medium, while growth of gram-positive organisms is inhibited.[2] Coliform organisms ferment the lactose in this medium, producing a green metallic sheen (i.e. Escherichia coli), whereas non-lactose-fermenting organisms produce clear, colourless colonies,[1] i.e. Salmonella species.
