Alexander Fleming Facts for Kids

Sir Alexander Fleming FRS FRSE FRCS, a distinguished Scottish physician and microbiologist, is best known for his groundbreaking discovery of penicillin, the world’s inaugural and widely effective antibiotic. His pioneering work in the field of medicine earned him the Nobel Prize in Physiology or Medicine in 1945 for this transformative achievement.

Portrait of alexander fleming


Alexander Fleming came into the world on August 6, 1881, in the Scottish hamlet of Darvel. His parents, Hugh Fleming and Grace Stirling Morton, both hailed from farming backgrounds. Tragically, his father’s health deteriorated, leading to his passing when Alexander was a mere seven years old. 

In his early education, Alexander attended a modest moorland school, where a single classroom accommodated 12 students of varying ages, ranging from five to eight. Subsequently, he enrolled in Darvel School, necessitating a daily eight-mile round-trip trek on foot. 

Alexander’s scholastic aptitude was evident from a young age, prompting an offer of a scholarship to Kilmarnock Academy at the age of 11. He spent approximately two years boarding at the academy before journeying to London. 

At the tender age of 13, in early 1895, Alexander relocated to London, coinciding with the release of Arthur Conan Doyle’s “The Memoirs of Sherlock Holmes,” which marked the fictional detective’s apparent demise at Reichenbach Falls. 

During his stay in London, Alexander resided in the home of his elder brother, Tom, a physician. The Fleming family collectively relocated to Tom’s residence, with the family estate passing to the eldest sibling, Hugh. 

At the Polytechnic School, Alexander initially pursued studies in business and commerce. However, his professors swiftly recognized his need for more rigorous academic challenges. Consequently, he was placed in a class with students two years his senior, culminating in his graduation at the age of 16.


Upon securing a position at a shipping office, Alexander’s dissatisfaction with the job was palpable. 

In 1901, at the age of 20, he received financial support from his uncle, John Fleming. Eager to follow in his accomplished brother Tom’s footsteps and pursue a career in medicine, Alexander allocated the funds to meet the prerequisites for medical school enrollment. 

He excelled in the necessary examinations, achieving the highest grades among all students in the United Kingdom. 

In 1903, at the age of 22, Alexander commenced his medical studies at London’s St. Mary’s Hospital Medical School. Three years later, he graduated with honors, earning a Bachelor of Medicine and Bachelor of Surgery degree. 

Rather than following his brother Tom’s path, Alexander heeded the counsel of immunology expert Almroth Wright, joining his bacteriology laboratory at St. Mary’s Hospital Medical School. 

Amid his research endeavors, Fleming earned a degree in bacteriology and was honored with the Gold Medal as the institution’s outstanding student in 1908. Subsequently, he assumed the role of bacteriology lecturer at St. Mary’s Hospital Medical School. 

Fascinated by Almroth Wright’s exploration of the human body’s intrinsic capacity to combat illnesses, Fleming was particularly intrigued by the notion that, although individuals occasionally succumb to bacterial infections, their natural defenses generally shield them from diseases.


In 1915, while serving as a captain in the Medical Corps, Alexander Fleming wed Sarah Marion McElroy. Their union brought forth a single son, Robert, who later became a general practitioner. 

In 1944, Fleming was granted the title of “Sir,” officially becoming Sir Alexander Fleming. Tragically, his wife Sarah passed away in 1949. 

In 1953, Fleming entered into matrimony once more, marrying Dr. Amalia Koutsouri-Vourekas, a member of his research group at St. Mary’s Hospital Medical School. 

On March 11, 1955, at the age of 73, Alexander Fleming succumbed to a heart attack in London, with his final resting place at St. Paul’s Cathedral.


Revelations Regarding Antiseptics

In 1914, at the age of 33, Alexander Fleming enlisted in the army, earning promotion to the rank of captain in the Royal Army Medical Corps. He diligently served in field hospitals situated in France. 

Through a series of ingenious experiments, Fleming made a critical discovery while in the military. He found that antiseptic medications, intended to heal wounds and prevent infections, were responsible for more soldier casualties than the diseases they aimed to combat. 

Antiseptics like carbolic acid, boric acid, and hydrogen peroxide failed to eliminate germs deeply embedded in wounds. Furthermore, these substances impeded the body’s natural resistance to infection by killing white blood cells. 

Fleming astutely determined that antiseptic chemicals were effective solely in treating surface wounds and posed hazards when applied to deeper lesions. 

Aligned with the views of his mentor Almroth Wright, who advocated the use of saline solution or saltwater to cleanse severe wounds without hindering the body’s intrinsic defenses, Fleming substantiated this concept. He provided empirical evidence to support the efficacy of saline solution. 

Regrettably, many army physicians remained resistant to altering their practices, resulting in avoidable casualties.

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Discovery of Lysozyme

In 1919, following his military service, Alexander Fleming returned to London’s St. Mary’s Hospital Medical School to embark on research endeavors. His experiences in the military underscored the importance of antibacterial agents that complemented, rather than undermined, the body’s natural defenses. Specifically, such agents should not harm white blood cells. 

At the age of 41, Fleming achieved a breakthrough in this regard. He extracted secretions from the nasal passages of a patient suffering from a head cold and cultivated any present bacteria. In these secretions, he identified a novel bacterium, initially named Micrococcus lysodeikticus and now recognized as M. luteus. 

A few days later, while he was afflicted by a head cold himself, Fleming inadvertently introduced mucus from his own nose to the cultured bacteria. Remarkably, the bacteria in the vicinity of the mucus were rapidly eradicated. 

Intrigued by this discovery, Fleming proceeded to investigate the impact of various bodily fluids, including blood serum, saliva, and tears, on these bacteria. He discerned that introducing a drop of any of these fluids inhibited bacterial growth. 

Fleming ultimately pinpointed an enzyme common to these bodily fluids, which he named lysozyme. This newly discovered enzyme possessed the remarkable ability to destroy certain types of microbes, rendering them harmless to humans. 

The presence of lysozyme within the human body conferred natural immunity against a range of maladies. However, the application of lysozyme as a medication was limited, as it exerted little to no effect on numerous other disease-causing bacteria.

Discovery of Penicillin 

Alexander Fleming achieved an epochal milestone in August 1928 that would revolutionize medicine. Following a prolonged vacation with his wife and son, he returned to his laboratory on September 3 to find a cluster of Petri dishes he had left on his workbench. These dishes contained colonies of Staphylococcus bacteria, and an open window during his absence had allowed various microbes to contaminate the dishes. 

While examining the dishes, Fleming discerned a peculiar occurrence in one of them: a fungus was flourishing and systematically eradicating bacterial colonies in its vicinity, while bacteria farther away remained unaffected. 

Intrigued by this phenomenon, Fleming entrusted the dish to an assistant, who astutely likened it to Fleming’s earlier discovery of lysozyme. 

Determined to explore this discovery further and identify a superior natural antibiotic to lysozyme, Fleming ascertained that the fungus belonged to the Penicillium genus. He subsequently developed a liquid containing the bacteria-killing substance produced by this fungus.

penicillin was discovered by alexander fleming

On March 7, 1929, Fleming publicly christened this antibiotic “penicillin” and unveiled its remarkable capabilities. His research demonstrated that penicillin could effectively eliminate a wide spectrum of germs, encompassing pathogens responsible for ailments such as scarlet fever, pneumonia, meningitis, and diphtheria. Crucially, penicillin exhibited non-toxicity and posed no harm to white blood cells. 

Nevertheless, Alexander Fleming’s groundbreaking discovery encountered various challenges, including difficulties in isolating penicillin from the fungus, challenges in producing it in large quantities, and its comparatively slow onset of action. Clinical trials further revealed that penicillin was ineffective as a surface antiseptic.

The Legacy of Penicillin 

Despite these challenges, Alexander Fleming persevered in his research on penicillin throughout the 1930s, although he did not achieve the breakthrough required to mass-produce the antibiotic. That milestone was reached by others. 

In the early 1940s, a team of scientists at the University of Oxford, led by pathologist Howard Florey and biochemist Ernst Boris Chain, successfully transformed penicillin into the therapeutic medication that has since saved countless lives. 

In recognition of their collective contributions to the discovery and therapeutic applications of penicillin, Alexander Fleming, Howard Florey, and Ernst Boris Chain were jointly awarded the Nobel Prize in Medicine or Physiology in 1945. 

In his Nobel Prize acceptance speech, Alexander Fleming cautioned against the misuse of penicillin and the potential development of antibiotic resistance, a prescient warning for the future of medicine. 

Fleming consistently credited and admired the work of Florey, Chain, and their research team while downplaying his own role in the penicillin story. Despite his inherent modesty, he attained international acclaim, and his groundbreaking achievement in medicine has saved millions of lives. 

In 1945, during a visit to the United States, chemical industries presented Alexander Fleming with a personal gift of $100,000 as a token of gratitude and appreciation for his monumental contributions. In keeping with his character, Fleming declined the personal gift and directed the funds toward research laboratories at St. Mary’s Hospital Medical School, perpetuating his commitment to scientific advancement.


Portrait of Alexander Fleming

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