Minimum Essential Medium is a commonly used modification of the Basal Medium acc. to Eagle, having been developed in 1959 for culturing of HeLa cells. MEM contains high concentration of amino acids, which conform closely to the protein composition of human cells. Concentration of vitamins, and other essential nutrients, is enhanced, allowing longer cultivation periods between feedings.MEM is one of the most widely used cell culture media and can be used for a variety of suspension cell cultures and adherent cells.

Generally, FBS is added to MEM basal media.

This modification of MEM contains Earle's salts, but no L-glutamine and no pyruvate.