Penicillin was one of the three major inventions during World War II, saving countless lives. The U.S. military discovered that penicillin could treat gonorrhea and syphilis in addition to fighting infections. That's a boon for Western militaries, which are deeply affected by sexually transmitted diseases. Penicillin has a special effect on Treponema pallidum and can bring a hapless soldier back into the field in a matter of days. The first recipient of the Lasker Prize in Medicine, known as the "Nobel Prize of America", was John F. Mahoney, a veteran of the U.S. Public Health Service, who pioneered the use of penicillin to treat syphilis.

Benzathine penicillin, also known as long-acting penicillin, is a white crystalline powder made of dibenzylethylenediamine salt mixed with suspension and buffer. After intramuscular injection, penicillin is slowly released and has antibacterial effect, which has the characteristics of slow absorption and long maintenance time. Clinically, it is mainly used for the treatment of early syphilis and the prevention of rheumatism recurrence. Benzathine penicillin has a longer duration of action and is sensitive to Treponema pallidum. After more than 60 years of use, there is no evidence that there is a risk of drug resistance. Therefore, many guidelines at home and abroad recommend benzathine penicillin as the drug of choice for clinical treatment of syphilis. In addition, benzathine penicillin is the only recommended drug for preventing mother-to-child transmission of syphilis.