A medical contribution of immense benefit was made of Upendranath (U.N.) Brahmachari (1875-1946). Originally a student of mathematics and chemistry, he joined the Campbell Medical School, Calcutta in 1905. Here, in a small laboratory, he worked from 1915 on a cure of kala-azar, a dreaded killer in Bengal and Assam. The traditional treatment by antimony (stibium in Latin) was long, tedious and painful, and therefore impracticable. In 1920, Brahmachari discovered an organic compound of antimony which he called Urea Stibamine. It had no painful effects, and was administered to patients at the Campbell Medical School Hospital and the Calcutta Medical College Hospital with great success. It was used on an experimental basis in Assam in 1923 and on a mass scale from 1928. By 1933 about 3.25 lakh lives had been saved in Assam alone. The medicine has also been used successfully in Greece, France and China; but contrary to popular belief, it was never patented.

To Brahmachari also goes the credit for establishing the first Blood Bank in India and the second of its kind in the world at Calcutta in September 1939.