Penicillin

A poster attached to a curbside mailbox in 1944 reminds US servicemen of the benefits of penicillin.

In 1928, Scottish scientist Alexander Fleming discovered penicillin, which became a successful treatment for previously dangerous diseases. During World War II, the use of penicillin on the battlefield resulted in major differences in the number of deaths and amputations caused by infected wounds, saving an estimated 12 to 15% of lives.