The modern idea of health as a human right is examined, as it evolved from the 18th century, in terms of its origins, its essential content, and 20th-century attempts at implementation. Equity for social groups is seen as a guiding principle. Two attempts at implementation, in Britain and in Cuba, are examined for their effects on equity in health service and in health states. The British National Health Service achieved equity between social classes in services but failed to achieve it in health states (as measured by mortality). Deficiencies in commitment to public health services, it is argued, contributed largely to this failure. The Cuban experiment appears to have moved beyond equity solely in services and toward equity in health states. This success reflects an overall Cuban commitment to the public health. Two important elements of that commitment are, first, continuous evaluation with flexible response and, second, community involvement.