 More specifically, acidophilia can be described by cationic groups of most often proteins in the cell readily reacting with acidic stains.It describes the microscopic appearance of cells and tissues, as seen through a microscope, after a histological section has been stained with an acidic dye.The most common such dye is eosin, which stains acidophilic substances red and is the source of the related term eosinophilic.