Penicillin

Penicillin is an antibiotic medicine that kills certain bacteria and was the first antibiotic discovered.

• Where it comes from: Penicillin was first found as a natural chemical made by a mould (a type of fungus). The mould releases it to stop bacteria growing nearby.
• How it works: It attacks the bacterial cell wall. Human cells do not have cell walls like bacteria, so penicillin can harm bacteria without harming most human cells.
• What it is used for: It is helpful in treating many bacterial infections (for example, some throat, skin, and chest infections), but it is not the right medicine for every bacterial disease.
• What it does NOT do: Penicillin does not work against viruses (like the common cold or flu), because viruses do not have the same structures as bacteria.
• Why it matters: Penicillin changed medicine by making many dangerous bacterial infections treatable, saving millions of lives.
• A key point to remember: Some bacteria have become able to survive penicillin (and other antibiotics). Using antibiotics only when prescribed and completing the full course helps slow this antibiotic resistance.