McCoy's 5A medium was designed by Thomas McCoy et al. in 1959, initially developed specifically for culturing Novikoff Hepatoma cells. McCoy's 5A medium is a modified version of Basal Medium 5A. Unlike other media, McCoy's 5A contains reduced glutathione, bacterial peptone, and high concentrations of glucose. McCoy's 5A is widely used for culturing various types of primary cells, such as bone marrow, skin, gingiva, kidney, spleen, lung, rat embryo, and retina. Additionally, McCoy's 5A medium is employed for tissue biopsy cultures, cell line establishment, and the cultivation of certain lymphocytes and difficult-to-culture cells.