How to tell if you actually need an antibiotic

A simple, non-diagnostic guide to the questions worth asking your GP or pharmacist before starting antibiotics. Informational only, not medical advice.

By Priya Nandan. Published 28 May 2026 · Clinically reviewed. This article is general information, not a substitute for advice about your own health.

Antibiotics help when an infection is caused by bacteria, and do nothing when it is caused by a virus. The trouble is that many illnesses can feel similar. This guide is informational only, and does not replace advice from a health professional who can assess you.

Questions worth asking

When you see your GP or pharmacist, it is reasonable to ask directly:

Is this infection likely to be bacterial or viral?
Will an antibiotic actually change how quickly I recover?
What should I watch for that would mean I need to come back?
What can I do to feel better if an antibiotic is not needed?

A good prescriber will welcome these questions. Sometimes the answer is a “wait and see” approach, where you hold off on antibiotics and only start them if things do not improve.

Signs that lean towards seeing a doctor

Symptoms that are severe, that keep getting worse after several days rather than better, or that come with a high fever, breathing difficulty or confusion, are reasons to be assessed rather than to wait. This is about getting the right care, not about pushing for a prescription.

The bottom line

The goal is the right treatment for the actual cause, which sometimes means antibiotics and often does not. For the full picture, read the complete guide to using antibiotics safely and our pillar on what you can do.