Chemotaxis is the movement of cells or organisms in response to a chemical stimulus. Chemotaxis cell culture assays are important experimental tools for studying the role of cell migration during development, such as the migration of neurons or lymphocytes. They can also elucidate how chemotaxis underlies various pathologies, such as the migration of immune cells to sites of injury or infection. Chemotaxis cell culture assays generally analyze two main types of chemotaxis: positive chemotaxis (movement towards a higher concentration of the chemical stimulus) and negative chemotaxis (movement in the opposite direction).