In the late 1970s, diarrhea was causing dehydration and millions of deaths per year in children under five. Since then, the number of such deaths has been reduced by more than 80%, in large part thanks to the simple idea that drinking a combination of sugar, salt, and potassium mixed in water can save a young child from dying from dehydration.

When physician-scientists funded by the NIH, CDC, and USAID arrived in Pakistan in the 1960s during a cholera outbreak, the treatment of choice to reduce deaths from cholera-induced diarrhea was intraveneous fluid delivery. However, access to intraveneous intervention was very limited in practice. Patients unable to get to a hospital faced a grim 30 to 40 percent mortality rate. Many alternatives had been tried, including treating dehydrated patients with a variety of oral solutions, from carrot soup to coconut milk. But the best treatment remained unknown.

With this as a backdrop, U.S. scientists David Sachar and Norbert Hirschhorn, who were on assignment in Pakistan, began working to understand what was happening in the gut cells when treated with a combination of glucose and sodium. Using a method developed for measuring potentials across frog skin, they experimented with various possibilities, and were eventually able to show that a mixture of sugar, salt, and potassium, dissolved in water, allowed for enhanced salt absorption. Salt is an essential element for rehydration. From there, they began giving patients this mixture orally and they found that it led to a very clear and substantial drop in diarrhea symptoms.

Since that first study, this simple, cheap treatment has saved millions of lives.