Bile Salts No. 3 is a mixture of bile salts for use in preparing microbiological culture media in a laboratory setting. Several media containing Bile Salts No. 3 are recommended in standard methods for multiple applications. Bile Salts No. 3 is not intended for use in the diagnosis of disease or other conditions in humans. Bile Salts No. 3 is a refined bile salts mixture, comprising mainly sodium cholate and sodium desoxycholate. Its primary use is as a selective agent for the isolation of Gram-negative micro-organisms, inhibiting Gram-positive cocci. Bile Salts No. 3 is prepared especially for use in MacConkey Agar and Violet Red Bile Agar. This fraction of bile is highly active allowing maximum selection of organisms of enteric origin at relatively low concentrations (0.15%) and is soluble in distilled or deionised water and neutral to slightly alkaline in pH.