Quality of life concepts and scales related to health (QLRH) are beginning to be customary in clinical practice and now play an important role in bioethical discussions, particularly concerning the management of terminal patients. This paper looks at how that concept has evolved and how it relates to the health-illness binomial. We illustrate some important complexities the notion of quality of life (QL) has borne since its inception and that make applicability in the health sciences difficult and, most of all, lead to tremendous biases. In our conclusions, we argue it is necessary to improve the concept of QL by including aspects and factors related to well-being. Although not entirely quantifiable, they give coherence and meaning to the patient data health professionals normally work with.