Epithelial Cell Growth Supplement-animal (EpiCGS-a) is a medium supplement designed for the optimal growth of normal animal (rat and mouse) Epithelial cells in vitro. It is a sterile, concentrated (100X) solution which contains growth factors, hormones, and proteins necessary for the culture of normal animal Epithelial Cells. The supplement is formulated (quantitatively and qualitatively) to provide a defined and optimally balanced growth environment that maximally promotes the growth of normal animal Epithelial Cells in vitro. The supplement is designed as an additive for Epithelial Cell Medium-animal (EpiCM-a, Cat. No. 4131) and should be used in conjunction with that medium.