The Little Prince is one of the most famous fables. In this paper, we attempt to look at three bioethical issues through the Little Prince's eyes: the end-of-life context, the patient–physician relationship and prevention/precaution. The fable gives us the basis for a perspective we have called ‘Medicine of the Invisible’, which is value-focused. The Little Prince suggests that we seek the invisible—the “thing that is important”, the “matters of consequence”, even on a gnoseological and epistemological level—as a new type of ‘clinical data’ which may help to make healthcare more ethical and effective. However, this invisible is attainable only within a relationship, in which the physician needs to be tamed by the patient and the patient needs to be tamed by the physician—each one becoming responsible for the other, each one becoming himself through the dialogue with the other. Responsibility is also projected towards the future, against those threats to life that are still unseen and unknown: owning a part of the world entails the ethical imperative to act, in order to safeguard life. But, without a relationship—saturated with lived time, shared experiences, and individual's uniqueness—no meaning and no value can be given. For this reason, the Medicine of the Invisible reminds bioethics that “the thing that is important is the thing that is not seen”.