Cell viability assays are laboratory techniques used to determine the health and survival of cells in culture. These assays help researchers assess the effects of various treatments, such as drugs or environmental conditions, on cell growth and death. Common methods include the MTT assay, which measures metabolic activity, and the trypan blue exclusion test, which distinguishes live cells from dead ones. These assays are essential in fields like pharmacology and toxicology, where understanding how substances affect cell health is crucial. By providing quantitative data on cell viability, these tests aid in drug development and safety assessments, ensuring that new therapies are both effective and safe for use.