The long upward trend in commodity prices showed signs of exhaustion at the end of 2014 (Chart 1). It is too early to evaluate whether it is the beginning of a down cycle, with considerable problems for exporting countries and possible relief for those dependent on imported commodities, including food. However almost certain is recurrent instability in the markets for these products, with strong influence of financial factors in price formation. It may be useful to remember the remarkable episode in Mexico eight years ago when prices reached unprecedented levels and the effects strongly affected population due to internal factors. As occurred in that country, the combination of international instability with domestic elements can have dangerous implications for food security of vulnerable populations.