Learn English: Alexander Fleming, discoverer of penicillin

Alexander Fleming: Discoverer of penicillin


Alexander Fleming was a Scottish scientist who is famous for discovering penicillin. He, and two other chemists, won the Nobel Prize for medicine because of this discovery.

Fleming recieving his nobel

Fleming was born on 6th August 1881 in Ayrshire, Scotland. He was the son of a farmer.  At the age of 13 he moved to London where he worked in a shipping office* for the next four years.  After, he began studying to be a doctor at St Mary’s Medical School, London University. His teacher was Sir Almroth Wright, a pioneer* in vaccine therapy.*

Fleming graduated in 1906 and after further study he became a lecturer at St Mary’s in 1908.  However, in 1914 World War One broke out*. Fleming joined the army and became a captain in the Army Medical Corps. During the war, in 1915, he married Sarah Marion McElroy of Killala, Ireland. Together they had a son who later studied medicine like his father.


The discovery of penicillin

After the war had ended, Fleming returned to St. Mary’s in London to work.  He was doing some studies on the bacteria streptococcus which causes sore throats and other infections. One day Fleming realised that something growing in a mold growing on top of an experiment was killing the bacteria in one of the dishes.  He tested the mold and tried to separate the substance in the mold that was killing the bacteria.  This substance become known as penicillin.  However, it was very difficult for Fleming to extract* the penicillin from the mold.


In June 1929 Fleming published his research in the British Journal of Experimental Pathology.  However, no one realised the importance of penicillin because it was very difficult to isolate*. This meant that scientists could not easily experiment with pure penicillin.

mold in dish Depositphotos_6858095_s-2015

Oxford University

However, chemists were still interested in penicillin and many tried to produce a pure form.  It was not until the Second World War that scientists were successful.  Scientists at Oxford University spent years trying to produce penicillin.  They used every type of container available, such as baths, kitchen pots and pans, to try to grow the mold that produces penicillin. It was a very difficult time as there was no research money available because of the war. 


Eventually the Oxford University chemists, Howard Florey, Ernst Chain and their colleagues, were able to start experimenting with the drug.  They discovered that penicillin cured* mice of the streptococcal bacteria.  The first human to receive the drug was a policeman who had cut himself on a rose thorn.  He recovered quickly from the infection but later died because there was not enough penicillin.

Mass production

However, the scientists made more penicillin and doctors were able to successfully treat patients.  Mass production* of penicillin was still very difficult because of the war. A couple of British companies started to produce the drug and then soon several American companies became involved.  More and more penicillin was produced and by 1945 it was available to the public in the UK as a prescription drug*.


In 1945 Alexander Fleming, Howard Florey and Ernst Chain were awarded the Nobel Prize for medicine for their research on penicillin.

Fleming became a fellow of the Royal Society in 1943 and the following year he was knighted ‘Sir Alexander Fleming.’  Sadly, in 1949, Fleming’s wife died.  He married again in 1953 to a colleague at St. Mary’s, Dr. Amalia Koutsouri-Voureka.


On 11th of March 1955 Alexander Fleming died.  He is buried in St. Paul’s Cathedral, London.

ST MARY'S HOSPITAL MEDICAL SCHOOL, PADDINGTON, LONDON - FEBRUARY 13: Plaque commemorating the discovery of Penicillin by Sir Alexander Fleming, taken from the public footpath on February 13, 2014 at St Mary's Hospital Medical School, Paddington, London, UK.
ST MARY’S HOSPITAL MEDICAL SCHOOL, PADDINGTON, LONDON – FEBRUARY 13: Plaque commemorating the discovery of Penicillin by Sir Alexander Fleming, taken from the public footpath on February 13, 2014 at St Mary’s Hospital Medical School, Paddington, London, UK.



Further reading:




Image ID:105031524


Image ID:6858095



Alexander Fleming: Discoverer of penicillin – vocabulary check

Shipping office – where men were hired to work at sea.

Pioneer – someone who is one of the first people to do something e.g. A pioneer of modern medicine.

Vaccine therapy – a vaccine contains a small amount of a virus or bacteria. This is given to someone to stop them getting the disease later on.

Break out – If something dangerous or unpleasant suddenly starts.

Extract (noun) – a substance taken from a plantflower, etc. and used especially in food or medicine.

Isolate – to separate something or someone from the things or people around it/them.

Cure (verb) ­– to make an ill person healthy again.

Mass production – to make a product in very large quantities.

Prescription drug – a medicine that must be prescribed for you by a doctor.

2 thoughts on “Learn English: Alexander Fleming, discoverer of penicillin”

  1. Good morning Lisa.
    My name is Ricardo and I am Spanish.
    Thank you very much for your publication on Alexander Fleming. It is one of my favorite characters. I am following your blog for some time now and I am learning a lot about the English language. It very useful and practical for me.
    keep it up. 🙂

Leave a Reply

Your email address will not be published. Required fields are marked *