Penicillin is an antibiotic used to treat a variety of bacterial infections. It works by damaging the cell walls of bacteria, which kills them or stops their growth

. Common uses of penicillin include treatment of:

• Strep throat and other throat infections
• Ear infections
• Skin infections
• Urinary tract infections (UTIs)
• Dental infections
• Respiratory infections such as pneumonia
• Meningitis caused by susceptible bacteria
• Syphilis and other sexually transmitted infections
• Certain serious infections like anthrax, tetanus, diphtheria, endocarditis, and rat-bite fever

Penicillin is effective mainly against infections caused by gram-positive bacteria and some gram-negative bacteria, although resistance has developed in some strains

. It is available in various forms including oral tablets, liquids, and injectable forms, with different types such as penicillin V (oral) and penicillin G (injectable) used depending on the infection

. Penicillin does not work against viral infections like colds or flu

. In summary, penicillin is primarily used to treat bacterial infections of the throat, ears, skin, urinary tract, respiratory system, and some serious systemic infections caused by susceptible bacteria