The tremendous success attained in the battle against disease with penicillin G not only led to the Nobel Prize being awarded to Fleming, Florey, and Chain, but to a new field of antibiotic research, and a new antibiotic industry. Penicillin opened the way for the development of many other antibiotics, and it still remains the most active and one of the least toxic of these compounds. Today, about 100 antibiotics are used to combat infections in humans, animals, and plants.