Penicillins are a type of antibiotic derived from Penicillium fungi. An antibiotic is a type of medicine that inhibits the growth of, or kills, bacteria. Penicillin G (also called benzylpenicillin).

Penicillins are a group of antibiotics originally obtained from Penicillium moulds, principally P. chrysogenum and P. Rubens. Most penicillins in clinical use are chemically synthesised from naturally-produced penicillins. Penicillin V potassium is used to treat certain infections caused by bacteria such as pneumonia and other respiratory tract infections, scarlet fever, and ear, skin, gum, mouth, and throat infections. 

Penicillins include:

• Amoxicillin.
• Ampicillin.
• Dicloxacillin.
• Nafcillin.
• Oxacillin.
• Penicillin G.
• Penicillin V.
• Piperacillin.