In 1943, Barry returned to Dublin on a fellowship in organic chemistry to work for the
Medical Research Council. He researched the chemotherapy of
tuberculosis, looking for a cure for TB which was a significant health issue in Ireland at the time. His work developed instead into an effective treatment for leprosy. Barry worked with
The Leprosy Mission in
Zimbabwe and
India to develop drugs against
tuberculosis and
leprosy. From 1950, he led a team of nine scientists, including
Frank Winder, J.G. Belton, Stanley McElhinney, M.L. Conalty, Seán O'Sullivan, and Dermot Twomey at
Trinity College, Dublin. They first synthesised B663 in 1954, and it was launched as the anti-leprosy drug
clofazimine in 1957. From the middle of the 1960s, Barry's research moved towards investigating the chemotherapy of cancer. Barry travelled the world lecturing and with his research team published over 170 papers. In 1950, Barry and his former mentor Thomas Dillon,
Ceimic, the first
chemistry textbook to be published in Irish. Barry advised
Tomás De Bhaldraithe on scientific terms when the later was developing a dictionary of modern Irish, published in 1959. ==Personal life==