This paper presents a genealogy of the vegetative life, as it has played a main role in medicine and philosophy for understanding living beings till the eighteenth century, but then became instead an indicator of a non- or in-human life. Two main periods might be distinguished: first, since Antiquity, humans, animals and plants share a very same form of life characterized as a vital spark which develops through organic transformation processes (nutrition, growth and generation). This conception places special emphasis on the interdependency between all the living things and gives a high value to vegetables considered as purest life. Early modern medicine interprets this essential life within the new frame of physiology and anatomy: Fernel and Vesalius describe vegetative life in human body as nutrition and growth, Harvey as circulation, Bordeu as regulation. Then from Bichat till today, the vegetative reference became less and less crucial for understanding human life; contemporary medicine emphasizes rather the distinction between human and other living beings, insofar only human beings are aware. By focusing on the levels of awareness and neglecting the common forms of vegetative life shared by all living beings, contemporary medicine sets the stage for transhumanism that overvalues consciousness and intelligence, and consequently claims to emancipate humans from their bodies. In this perspective, transhumanism appears as an issue that was historically made possible by the conceptual change of the epistemic category of vegetative state.