This paper seeks to respond to some of the recent criticisms directed toward bioethics by offering a contribution to a "critical bioethics". Here this concept is principally defined in terms of the three features of interdisciplinarity, self-reflexivity and the avoidance of uncritical complicity. In a partial reclamation of the ideas of V.R. Potter, it is argued that a critical bioethics requires a meaningful challenge to culture/nature dualism, expressed in bioethics as the distinction between medical ethics and ecological ethics. Such a contesting of the "bio" in bioethics arrests its ethical bracketing of environmental and animal ethics. Taken together, the triadic definition of a critical bioethics offered here provides a potential framework with which to fend off critiques of commercial capture or of being "too close to science" commonly directed toward bioethics.