Although able to extend the life of some critical patients, advanced medical technology is limited in terms of scope and extent of effectiveness. Some patients die despite the best efforts of medical teams. Medical futility describes treatments that are both extremely unlikely to benefit a patient and costly to provide. Clearly defining futile treatments and considering this concept in patient care strategies is important to provide quality patient care. Taiwan is currently formulating a policy on medical futility. While accepting that the term "futile" is used in many different ways and that this term is difficult to define in clinical practice, this article discusses the various ethical views on medical futility and its definition, the debate among these different views, and related research. We hope this article may help medical care staff better understand the importance of medical futility.