The term “antibiotic” is from the Greek meaning “against life.” In 1889, French mycologist Jean Paul Vuillemin (1861–1932), a pupil of Louis Pasteur’s, used the term to describe the substance pyocyanin, which he had isolated several years earlier. Pyocyanin inhibited the growth of bacteria in test tubes but was too lethal to be used in disease therapy. Now we know antibiotics as chemical products or derivatives of certain organisms that inhibit the growth of other organisms, or even a chemical substance produced by one organism that is destructive to another.