Everyday Antibiotics & You
Do antibiotics work on colds and the flu?
The short answer is no. Colds and flu are caused by viruses, and antibiotics only work on bacteria. Here is what that means for you.
By Dr James Okafor. Published 1 July 2026 · Clinically reviewed. This article is general information, not a substitute for advice about your own health.
No. Colds and influenza are caused by viruses, and antibiotics only work against bacteria. An antibiotic will not shorten your illness, ease your symptoms, or stop you passing the virus on.
Why this matters
Taking an antibiotic you do not need still has a cost. It exposes the harmless and helpful bacteria you carry to the drug, which gives resistant strains room to thrive. It can also cause side effects such as diarrhoea, thrush, or an allergic reaction, for no benefit.
What actually helps a cold or the flu
Rest, fluids, and time do most of the work. Simple measures such as paracetamol or ibuprofen for aches and fever, and saline sprays for a blocked nose, can make you more comfortable. Your pharmacist can recommend symptom relief that suits you.
When a bacterial infection is possible
Sometimes a viral illness is followed by a bacterial one, for example a chest or sinus infection that is getting worse rather than better after several days. That is a reason to see your GP, who can assess whether an antibiotic is genuinely needed. It is not a reason to start one “just in case.”
For a wider view, read the complete guide to using antibiotics safely or our pillar on preventing antibiotic resistance.
General practitioner and antimicrobial stewardship lead. Reviewed 3 July 2026 · Next review due July 2027 ·View reviewer profile and credentials