MacConkey Broth is a selective and differential liquid medium intended for selection and isolation of enteric gram-negative bacilli, such as coliforms. The original formulation of MacConkey Broth, developed by MacConkey in 1900, contained 0.5% sodium taurocholate (inhibitor) and litmus (indicator). Several iterations were subsequently proposed and in 1905 litmus was replaced with neutral red. In 1953, Childs and Allen replaced neutral red with bromocresol purple after studies demonstrated it was less inhibitory. Sodium taurocholate has also been replaced with oxgall in the current formulation for the inhibition of gram-positive organisms. • Product meets CLSI, ISO, Harmonized USP/EP/JP, and WHO reference methods and performance criteria.• For in vitro diagnostic (IVD) use.• MAC Broth should be used by trained professionals within a laboratory setting. • Product is not intended for use in the diagnosis or treatment of disease or other human conditions.