Which two researchers were pivotal in bringing penicillin to clinical use during World War II?

• A. Howard Florey and Ernst Boris Chain
• B. Alexander Fleming and Howard Florey
• C. Louis Pasteur and Joseph Lister
• D. Howard Florey and Ernst Boris Chain

Answer: (D)

The crucial idea here is turning a discovery into a real therapy. Alexander Fleming observed penicillin’s antimicrobial effect, but turning that observation into a usable drug required solving production, purification, and clinical testing challenges. Howard Florey and Ernst Boris Chain took penicillin from the lab to the bedside: they purified it, developed ways to produce it in larger quantities, and led early human trials at Oxford during the war. Their work demonstrated that penicillin was safe and effective in treating infections, which, with wartime collaboration to scale up production, made mass use possible. This is why they are credited with bringing penicillin into clinical use during World War II, a contribution recognized with the Nobel Prize in Physiology or Medicine awarded to Fleming, Florey, and Chain.