Sir Alexander Fleming died at his home in London from a heart attack. He was buried in St Paul's Cathedral, marking the end of the life of the discoverer of penicillin.

After the death of his first wife, Alexander Fleming married Amalia Koutsouri-Vourekas, a Greek colleague at St. Mary's. This marked his second marriage.

Alexander Fleming delivered his Nobel Prize lecture, acknowledging the importance of penicillin and briefly mentioning his earlier discovery of lysozyme. He shared the Nobel Prize in Physiology or Medicine with Howard Florey and Ernst Chain for the discovery of penicillin.

Alexander Fleming cautioned about the dangers of misusing penicillin in a speech, warning that microbes could become resistant to the drug if used improperly. He emphasized the responsibility of using penicillin wisely to prevent the development of penicillin-resistant organisms.

Despite initial reports crediting penicillin, Winston Churchill was actually saved by the new sulphonamide drug sulphapyridine (M&B 693) when he fell ill in Carthage, Tunisia, during World War II. This detail corrects a common misconception about Churchill's treatment.

The Penicillin Committee was created, chaired by Sir Cecil Weir, with Fleming, Florey, and other scientists and representatives from pharmaceutical companies as members. The committee was formed to rapidly produce penicillin in large quantities for Allied armed forces.

A meeting was convened by Sir Cecil Weir, Director General of Equipment, to discuss the mode of action of penicillin. This meeting was prompted by the successful treatment of Harry Lambert and marked a significant step towards recognizing the importance of penicillin.

Cecil George Paine, a pathologist and former student of Fleming, successfully used penicillin to cure eye infections (conjunctivitis) in one adult and three infants (neonatal conjunctivitis) at the Royal Infirmary in Sheffield. This was the first documented successful medical treatment using penicillin.

Alexander Fleming officially named the antibacterial substance derived from the Penicillium mould 'penicillin'. This was a crucial step in identifying and defining the potential therapeutic agent he had discovered.

Fleming began his first clinical trial of penicillin by treating his research scholar Stuart Craddock, who had developed a severe infection of the nasal antrum (sinusitis). This marked the initial attempt to use penicillin as a treatment, though it proved ineffective due to the nature of the infection.

Fleming published his discovery of lysozyme in the Proceedings of the Royal Society B: Biological Sciences, under the title "On a remarkable bacteriolytic element found in tissues and secretions." This publication formally introduced lysozyme to the scientific community.

Alexander Fleming married Sarah Marion McElroy in Killala, County Mayo, Ireland. Sarah was a trained nurse. This marked a significant event in Fleming's personal life, establishing his family.