Benzathine benzylpenicillin, also known as benzathine penicillin G, is an antibiotic medication useful for the treatment of a number of bacterial infections. Specifically it is used to treat strep throat, diphtheria, syphilis, and yaws. It is also used to prevent rheumatic fever. It is given by injection into a muscle. It is known as "Peanut Butter Shot" in US military slang due to its viscosity. From Wikipedia