Alexander Fleming

Alexander Fleming was a scientist (bacteriologist) who discovered penicillin, the first widely used antibiotic.

• He worked with bacteria in a laboratory, often growing them in shallow plates called petri dishes.
• In 1928, he noticed that a patch of mould had accidentally grown in one dish, and the bacteria near it were not growing.
• He understood that the mould was releasing a substance that could kill or stop bacteria. He named this substance penicillin.
• This was a turning point in medicine because antibiotics made it possible to treat many dangerous bacterial diseases that earlier could become life-threatening.
• A useful idea to remember: Fleming’s discovery was chance, but the real science was his careful observation and reasoning—he noticed something unusual and investigated it instead of ignoring it.

Fleming’s work shows how a single discovery can change healthcare for millions of people when it leads to effective treatments.