Penicillin G is a type of antibiotic that belongs to the penicillin family. It is primarily used to treat bacterial infections, particularly those caused by Streptococcus and Neisseria species. Penicillin G is effective against a variety of infections, including pneumonia, meningitis, and syphilis. This antibiotic is usually administered through injection, as it is not well absorbed when taken orally. Penicillin G works by interfering with the formation of bacterial cell walls, ultimately leading to the death of the bacteria. It is important to use this medication under the guidance of a healthcare professional to avoid resistance and ensure effectiveness.