For adventurous travelers, diarrhea is merely an embarrassing nuisance. But among poor people it is a killer. As many as half a million children are thought to die every year from enteric diseases, including cholera and dysentery. Repeated infections also 16 them, laying them open to attacks from other killers such as pneumonia. Diarrhea can even change the average 17 of a certain population. One reason Indian children are shorter than sub-Saharan African children from families of similar means is that they fall sick more often. Bangladesh, one of Asia's poorest countries, is making huge progress 18 this misfortune. In one part of the country with particularly good data, deaths from diarrhea and other enteric diseases have fallen by 90% in the past two decades. Along with a far-reaching 19 program and steady economic growth, that has helped drive down the number of childhood deaths. In 1990 the under-five death rate in Bangladesh was 54% higher than the world average. Now it is 16% lower. In a country with more than 160 million inhabitants, this represents a vast 20 in human misery. Bangladesh's success holds lessons for other poor countries that are trying to beat back disease.