There is a move away from a market economy in health care in the United States and a move towards such a market in Germany.1 This article tries to make explicit what underlies the moral intuition that there is a tension between a market economy and health care. First, health care is analyzed in terms of the economic theory of the market and incompatibilities are described. The moral problem is identified as the danger of liquefying the distinction between persons and things . The basic moral intuition seems to be the classical social contract: as a functioning market is governed by the principle of commutative justice , free riders have to be kept away, which is achieved by coercion that is not provided by the market; coercion can be justified by a social contract. The special moral problems of a social contract for health care are discussed. It is argued that public coercion in order to collect contributions for essential health care is justified.