<human>:  Who discovered Penicillin?
<bot>: Alexander Fleming discovered Penicillin in 1928. Fleming was a bacteriologist who worked at St Mary's Hospital in London. He was studying a strain of bacteria when he noticed that one of his cultures had been infected by a fungus. He then realized that the fungus had killed the bacteria, and that it could be used to treat infections. He called the fungus Penicillium notatum, and the antibiotic penicillin was born.