After graduating in Medicine from the University of St Andrews, Black became a lecturer in Malaya. He was appointed a lecturer at the University of Glasgow's Veterinary School in 1950 and established the Physiology Department. In his Nobel Prize Autobiography, he writes of this time:
"[William Weipers] gave me the opportunity to start a new Physiology Department, and during the next eight years I built a state-of-the-art physiology teaching laboratory based on my enduring belief that our brains work best when doing focuses our thinking....I built a workshop-coupled research laboratory providing the most advanced cardiovascular technology I knew... I slowly learned, like a primitive painter, how to be an effective experimenter, ideas began to ferment."
His subsequent development of propranolol, the beta adrenergic receptor antagonist (beta-blocker) in the late 1950s, which revolutionized the medical management of angina, is considered one of the most significant contributions to clinical pharmacology of the 20th century. Similarly, his work on histamine receptors in the stomach led to the development of the H-2-antagonist cimetidine, which inhibits the action of histamine on the acid-secreting cells of the stomach wall. Cimitidine was approved by the US Food & Drug Administration in 1977 and when marketed as ‘Tagamet’ became the highest selling drug in the world. Propranolol and Cimitidine continue to be in widespread use throughout the world today.