[citation needed] He is a specialist in the treatment of diarrheal diseases such as cholera in the developing world.
[2][3] In 1984, Greenough was awarded the King Faisal International Prize in Medicine for research on diarrhea with John S. Fordtran and Michael Field.
[3] For his services to children, UNICEF awarded him the Gold Medal for East Asia and Pakistan in 1983 and the Maurice Pate Prize in 1984.
He was named the 2001 Howard Florey Memorial Lecturer at the University of Adelaide as well as the 2006 Paul G. Rogers Society Ambassador for Global Health Research.
[4] He received the Mary Betty Stevens Award for Excellence in Clinical Investigation prize from the American College of Physicians in 2012, and the Arnold P. Gold Foundation Humanism in Medicine Award from the American Geriatric Society in 2014.