High Content Screening: a method that is used in biological research and drug discovery to identify substances such as small molecules, peptides, or RNAi that alter the phenotype of a cell in a desired manner. Hence high content screening is a type of phenotypic screen conducted in cells. Phenotypic changes may include increases or decreases in the production of cellular products such as proteins and/or changes in the morphology (visual appearance) of the cell. High content screening includes any method used to analyze whole cells or components of cells with simultaneous readout of several parameters.