This is an enriched variation of Minimum Essential Medium, containing all 21 normal amino acids, and 5 additional vitamins. Minimum Essential Medium (MEM) is a common cell culture medium developed from early work with Basal Medium Eagle (BME). It is modified with higher concentrations of amino acids to more closely approximate the proteincomposition of mammalian cells. When supplemented with serum, MEM has been used for cultivation of a wide variety of cells grown in monolayers, such as fibroblasts.