Cell viability assays are laboratory techniques used to determine the health and survival of cells in culture. These assays measure the ability of cells to grow and proliferate under various conditions, such as exposure to drugs or toxins. Common methods include the MTT assay, which assesses metabolic activity, and the trypan blue exclusion test, which distinguishes live cells from dead ones. These assays are essential in research and drug development, helping scientists evaluate the effectiveness of treatments and understand cellular responses. By providing insights into cell health, cell viability assays contribute to advancements in fields like cancer research and toxicology.