Today marks the 20th installment in a series of articles by titled, Heroes of Progress. This bi-weekly column provides a short introduction to heroes who have made an extraordinary contribution to the well-being of humanity. You can find the 19th part of this series here.

This week, our Hero of Progress is David Nalin, the scientist who developed the precise formula for oral rehydration therapy (ORT). Nalin led the team that carried out the first successful trials of ORT and helped to spread its use around the world. ORT is used to rehydrate patients who are suffering from illnesses that cause severe dehydration. It is estimated that since its creation in 1968, ORT has saved more than 70 million lives.

Before ORT was discovered, the only effective way to rehydrate a patient suffering from serious dehydrating illnesses, such as cholera, was to provide fluids intravenously. Intravenous therapy (IV) is an expensive and often inaccessible treatment, as it requires modern medical facilities that are often unavailable in poorer nations. If left untreated, cholera can kill a healthy person in just a few hours. That is where David Nalin enters our story.

David Nalin was born on April 22, 1941 in New York City. Nalin attended the Bronx High School of Science and in 1957 he enrolled to study a Bachelor of Arts degree in zoology at Cornell University. After graduating from Cornell in 1961, Nalin secured a place at Albany Medical College and, four years later, he earned his medical doctorate.

After spending a year as a medical intern at Montefiore Hospital in New York, Nalin moved to Dhaka in 1967. In the capital of East Pakistan, he worked on cholera for the Southeast Asia Treaty Organization (SEATO). The following year, a large cholera epidemic broke out in Dhaka and Nalin quickly realized that the existing IV therapy that was used to treat cholera was too costly and slow to administer.

Working from a small missionary hospital in the jungle of what is today Bangladesh, Nalin led a small team of researchers to develop and complete the first successful trial for oral rehydration therapy. ORT mixes salts and sugars with water in order to replace the minerals that the patient lost due to diarrhea or vomiting. The salts are needed for organ function and the sugars help the salts to be absorbed in the intestines.

Nalin himself admitted that ORT is a very simple solution, but the nuance in his discovery comes from the very specific ratios of water, salt and sugar needed for the treatment to work effectively. ORT packets are very cheap and cost just between 3 and 4 U.S. cents to produce. It doesn’t need to be administered by medical professionals. It also uses between 70 and 80 percent less fluid than is needed with IV therapy.

In 1969, Nalin began working as a consultant for the World Health Organization. He helped to successfully establish ORT programs to combat diarrheal diseases around the world, including Costa Rica, Jamaica, Jordan and Pakistan. In 1971, during the Bangladesh Independence War, ORT helped to reduce the cholera mortality rate from 30 percent to just 3.6 percent.

In 1978, the prestigious British medical journal The Lancet called ORT “potentially the most important medical advance of this century.” Similarly, in 1987, the United Nations Children’s Fund (UNICEF) noted that “no other single medical breakthrough of the 20th century has had the potential to prevent so many deaths over such a short period of time and at so little cost” than ORT.

From 1983 until his retirement in 2002, Nalin held several different director positions at Merck Research Laboratories. In 2002, Nalin received the first ever Pollin Prize in Pediatric Research. In 2007, he received the Mahidol Medal, an award for outstanding achievements in medicine and public health, from the King of Thailand. Since his retirement, Nalin continues to work as a consultant in vaccinology. He is currently Professor Emeritus at Albany Medical College.

In addition to the 70 million lives that ORT already saved, Nalin’s discovery continues to save thousands more lives every day. For that reason, David Nalin is our 20th Hero of Progress.