Absence of financial protection in health is a recently diagnosed "disease" of health systems. The most obvious symptom is that families face economic ruin and poverty as a consequence of financing their health care. Mexico was one of the first countries to diagnose the problem, attribute it to lack of financial protection, and propose systemic therapy through health reform. In this article we assess how Mexico turned evidence on catastrophic and impoverishing health spending into a catalyst for institutional renovation through the reform that created Seguro Popular (Popular Health Insurance). We present 15-year trends on the evolution of catastrophic and impoverishing health spending, including evidence on how the situation is improving. The results of the Mexican experience suggest an important role for the organisation and financing of the health system in reducing impoverishment and protecting households during periods of individual and collective financial crisis.