Background: Antibiotics revolutionised surgery; dramatically reducing the risk of post-surgical infections, making operations safer and more successful, crucial in the advancement of modern surgical practices. While the Nobel prize for the discovery of penicillin was awarded to Alexander Fleming, Howard Florey, and Sir Norman Heatley, another major contributor to this advancement was Mary Ethel Florey. History: Mary Ethel Florey (née Hayter Reed) born 1 Oct 1900 Stanmore, Sydney. She completed an MBBS from the University of Adelaide in 1924 and MD in 1950. While a student at university, she met Howard Florey, who in 1921 was awarded a Rhodes Scholarship, living abroad for 5 years during which they maintained a long-distance relationship. In 1926 Mary joined him in London and they were married in Paddington. She worked with the Oxford Regional Blood Transfusion Service 1939-41; running the first clinical trials of penicillin in military hospitals along with her lab partner and husband Howard Florey. Mary Florey introduced Howard to the first patient to be treated with penicillin, police constable Albert Alexander. Howard Florey stated that without her “penicillin would not have been introduced into medical practice when it was.” After collaborating with her husband on the book, Antibiotics, she published her own, The Clinical Application of Antibiotics (London), in four volumes. Mary suffered from ill health most of her life and was partially deaf, making her contributions to medicine even more remarkable. Florey played a critical role in the clinical application of penicillin. Her work, often overshadowed by her male counterparts, was essential in making antibiotics commonplace in medicine and surgery.