In 1928 Alexander Fleming (1881-1955) observed that mould had developed accidently on a staphylococcus culture plate and that the mould had created a bacteria-free circle around itself. He was inspired to further experiment and he found that a mould culture prevented growth of staphylococci and several other microbes.
He named the active substance penicillin. In 1938 production of penicillin in larger scale started.
First patients treated by penicillin were RAF pilots during the 2nd World War. Since 1944 first experiments with penicillin production in chemical-pharmacological factory in Dolní Měcholupy were made.