In what is now Kishoreganj, Bangladesh, on 12 November 1934, a boy named Dilip Mahalanabis was born. He studied medicine at Calcutta Medical College, trained further in London and Edinburgh, and became a paediatrician with a special interest in diarrhoeal diseases.

In 1966 he joined the Johns Hopkins University research centre in Calcutta, studying oral rehydration—the idea that a simple mixture of sugar, salt and water could replace the fluids lost in cholera and severe diarrhoea. The theory was known; large-scale proof was still missing.

Then came 1971. As war raged in East Bengal, hundreds of thousands of refugees poured into West Bengal. Cholera swept through the overcrowded camps near Bangaon. Intravenous fluids ran out. Trained staff were too few. Patients lay on the ground in their own waste.

Dilip faced a choice. He mixed glucose, common salt and baking soda in water, called it “oral saline,” and taught relatives to give it to the sick. Within weeks the death rate in his camp fell from nearly thirty percent to under four percent.

One exhausted colleague asked him, “Are you sure this will work when people are so sick?”

Dilip answered steadily, “We have no more IV fluid. This is what we have. And the patients are drinking it. That is enough to begin.”

The results spoke louder than any argument. The World Health Organization took notice. Oral Rehydration Solution—ORS—became a cornerstone of global diarrhoea control. The Lancet later called it one of the most important medical advances of the twentieth century. Millions of children’s lives were saved.

He went on to work for WHO in Afghanistan, Egypt and Yemen, directed research at the International Centre for Diarrhoeal Disease Research in Bangladesh, and received the Pollin Prize and the Prince Mahidol Award. He died in Kolkata on 16 October 2022. The following year India awarded him the Padma Vibhushan posthumously.

From the research labs of Calcutta to the desperate refugee camps of 1971 and the medicine cupboards of the world, Dr. Dilip Mahalanabis turned a simple mixture of sugar and salt into one of the greatest life-saving tools humanity has ever known.