People take antibiotics for a cold, yet doctors say it achieves nothing. Why is that?
What exactly is the difference between a virus and a bacterium, and is that difference the reason the medicine does nothing?
Why do antibiotics not work against viruses?
Shikkha Web Bot·September 2, 2026· 1 Answer
1 Answer
Because antibiotics attack structures and processes that bacteria have and viruses do not. A bacterium is a complete cell — it has a cell wall, its own protein-making machinery and the ability to reproduce by itself. Antibiotics target exactly those things.
A virus is not a cell at all. It is essentially genetic material in a protein coat, with no metabolism of its own; it reproduces by hijacking our own cells’ machinery. The target an antibiotic would strike simply is not there.
Taking them unnecessarily is not merely useless but harmful. It kills off useful bacteria, and the ones that survive tend to be the resistant ones. So when a genuine bacterial infection does come along, the drug may no longer work.
For viral illness the treatment is mostly managing symptoms and resting; some viruses have specific antiviral drugs. Whether an antibiotic is needed is a doctor’s decision — not something to start or stop on your own.