Discovery of Penicillin
In 1928, Alexander Fleming made a groundbreaking discovery that would change the course of medicine forever.
Accidental Discovery
- In September 1928, while working at St. Mary's Hospital in London, Fleming returned from a two-week vacation.
- He noticed that a petri dish containing Staphylococcus bacteria had been contaminated by mold.
- The mold, later identified as *Penicillium notatum*, had created a bacterial-free circle around it.
Significance of the Discovery
- Fleming realized that the mold was producing a substance that inhibited bacterial growth, which he named penicillin.
- This marked the first true antibiotic, leading to the development of penicillin as a treatment for bacterial infections.
- Fleming published his findings in 1929, but it did not gain immediate attention.
Development into Medicine
- During World War II, the potential of penicillin was recognized, leading to a concerted effort to mass-produce it.
- Scientists Howard Florey and Ernst Boris Chain played crucial roles in developing production methods that made penicillin widely available.
Impact on Medicine
- Penicillin became essential in treating infections, significantly reducing mortality rates from bacterial diseases.
- Its discovery paved the way for the development of other antibiotics, revolutionizing modern medicine.
In summary, Alexander Fleming's discovery of penicillin in 1928 was a serendipitous event that laid the foundation for antibiotic therapy, ultimately saving millions of lives and transforming the field of medicine.

November 19, 1999,