Penicillin is one of the three great inventions in World War II. Besides penicillin, two other inventions were the atomic bomb and radar. British Prime Minister Winston Churchill once commented that penicillin was "the greatest invention of World War II".

The discovery of penicillin can no longer be accidental, just like a gift from heaven to mankind. 1928, the bacteriologist Fleming accidentally forgot the bacteria being tested in the laboratory and went on vacation, which caused the bacteria in the Petri dish to be exposed to the air for three weeks. When Fleming came back, he found that staphylococci that had been in contact with bacteria had grown a group of green molds, which dissolved the surrounding staphylococci colonies. With the scholar's intuition, he studied this turquoise mold and penicillin was discovered.

However, the purification of penicillin did take a lot of effort, and it was a coincidence that penicillin could be produced in large quantities. Once Flory's men, who specialized in producing penicillin and selling fruits in the market, suddenly found a cantaloupe covered with mold. However, this researcher has been doing experiments with Flory, and thought that this mold looked strange, so he took it back to the laboratory for experiments. A study really found that this strain on cantaloupe can increase the dose of penicillin to more than 2000 times. After a series of studies, penicillin can finally be put into use.

After penicillin was discovered and put into use in large quantities, many wounded people were rescued in time, which was affectionately called "life-saving medicine" by soldiers in World War II. The most important function of penicillin is not to improve the survival rate of soldiers in the war, but to promote the birth of antibiotic family. Mr. Sun Zhongshi said: "The use of antibiotics has extended people's average life expectancy by 24 years." It is well-deserved to say that penicillin has changed the course of mankind.