Prior to 1977, tests for epidermal responses to substances were carried out primarily on animals, which generally produced misleading results. In order to effectively, and safely, investigate reactions in human subjects Griffith and Buehler developed the ‘repeated-insult patch test’. By concentrating and localising samples of the substance to a small, confined grid of 12mm, researchers were now able to observe results on humans much more quickly and more accurately than with animals. This is an example of an alternative technique that not only replaces the need for animals, but ultimately generates better results.