Antibiotics are not new. Their actions probably were first observed by Pasteur in 1877. However, the second quarter of the 20th century marked the flowering of the antibiotic era – a new and dramatic departure in the production of disease-fighting drugs. Fleming’s discovery of penicillin in 1929 went undeveloped and Florey and Chain studied it in 1940. Under pressure of World War II, the pharmaceutical manufacturers rapidly adapted mass production methods to penicillin; have reduced costs to 1/1000th the original. Antibiotic discoveries came rapidly in the ’40’s. Intensive research continues to find antibiotics that will conquer more of men’s microbial enemies.