||It is widely recognized that health systems should not only improve the health status of the population but also protect households from the adverse economic consequences of health shocks. The share of public funding in the overall financing of health services, and the extent to which services are prepaid, are indicators of the capacity of the health system to provide this protection to households. Evidence of the economic vulnerability of households in the face health shocks can be a catalyst of reforms that improve access and equity. A case in point is Mexico. In the nineties, when evidence became available of the great extent to which Mexicans had to rely on out-of-pocket payments and private services, it became clear that there was a wide and inequitable gap in public service coverage. This vulnerability is even greater in periods of economics crisis. Evidence of this, as well as of the high incidence of catastrophic expenditures at the household level due to health shocks, provided the rationale for a reform process that lead to the creation of the Seguro Popular, a social health insurance that entitles Mexican citizens to an explicit benefit package.