The chapter analyses two questions: first, how should we evaluate the effects of medical tourism? Second, who should be held responsible for these effects? The first question is answered by presenting four theories of justice that can be applied to the outcomes of medical tourism. These theories do not generate a common answer on a considerable number of points. The second question is answered by referring to the liability model of responsibility. In order to avoid over-inflated obligations, responsibility should be linked to causation of harm. A flexible application of this principle attributes responsibility to states for the negative consequences of their own policy and to medical tourists for the health care capacity reduction in destination countries when health care services outside the package of decent health care are pursued.