Alexander Fleming and Penicillin When Sir Alexander Fleming treated a large number of soldiers who got injured as an army surgeon, he noticed that antiseptic solution was not useful. In the first World War, the wounded had festering wound, and the medicine of that time, no one able to cure it. Therefore he began to research on the disinfectant material. He cultured many bacteria and repeated an experiment. One day tidying his messy room , he found that green mold spread on the medium which cultured bacteria. It happened by mistake. He left the cover of the bottle of the medium. At that time he noticed that bacteria disappeared around the green mold . He thought that the green mold may have an ingredient which had killed bacteria, he discovered a disinfectant material in filtration of the green mold. The material which discovered in the green mold was named penicillin. Penicillin is known as the first antibiotic in the world and saved a lot of people.