Antibiotics: why you should not take them without advice
Last reviewed 23 October 2026
Short answer: Antibiotics treat infections caused by bacteria. They do not work on viruses, which cause most colds and flu. Using them when they are not needed, or in the wrong way, can cause side effects and helps bacteria become resistant, which makes future infections harder to treat. Use an antibiotic only when a doctor or pharmacist advises it, and take it exactly as directed.
What antibiotics do, and what they do not do
An antibiotic is a medicine that kills bacteria or stops them from growing. It is useful for bacterial infections, such as some throat, chest, urine and skin infections, when a doctor decides one is needed.
It will not help with illnesses caused by viruses. These include the common cold, most sore throats, influenza (flu) and most coughs. Taking an antibiotic for a viral illness does not make you better faster, and it can cause side effects such as an upset stomach, diarrhoea or an allergic reaction.
Why misuse is a serious problem
When antibiotics are used too often, for the wrong illness, or not as directed, some bacteria survive and learn to resist the medicine. This is called antibiotic resistance. Resistant infections can be harder, slower and more expensive to treat, and in some cases they can be dangerous. The World Health Organization describes antimicrobial resistance as a major global health threat, and it affects everyone, not just the person who took the medicine.
Common mistakes
| Mistake | Why it is a problem |
|---|---|
| Taking an antibiotic for a cold or flu | It does not work on viruses, and it exposes you to side effects and resistance for no benefit. |
| Buying one without asking, because "it worked last time" | A different illness, or the same symptoms with a different cause, may need different treatment. |
| Using leftover tablets from an old illness | They may be the wrong medicine, the wrong amount, or expired. See medicine expiry dates explained. |
| Sharing antibiotics with family or friends | What suits one person may not suit another, and allergies and other conditions differ. |
| Stopping or changing the course on your own | An incomplete or irregular course can leave some bacteria alive. Ask your doctor or pharmacist before you stop. |
| Choosing by price or brand alone | The right antibiotic depends on the infection, and a cheaper or more expensive pack is not necessarily the right one. |
If a doctor prescribes an antibiotic
- Take it exactly as directed: the right medicine, strength, number of times a day and number of days. See how to read a prescription if the shorthand is unclear.
- Ask before you stop early. If you feel better before the course ends, ask your doctor or pharmacist what to do rather than deciding yourself.
- Tell the doctor about allergies, especially any past reaction to an antibiotic, and about any other medicines you take.
- Do not save leftovers for another illness, and do not give them to anyone else.
- Report a reaction. If you get a rash, swelling, difficulty breathing or severe diarrhoea, stop and get medical help straight away.
Questions to ask your pharmacist
- Is an antibiotic actually the right medicine for this illness?
- How should I take it, with or without food, and for how many days?
- What side effects should I watch for?
- Is it safe with my other medicines?
- What should I do if I miss a dose?
Our list of 10 questions to ask your pharmacist will help you at the counter.
Safer ways to look after yourself with a cold or flu
For a viral illness, rest, fluids and treating the symptoms are usually the approach, and a pharmacist can suggest suitable options. Be careful if you use more than one cold or flu product, because they often share ingredients. Read how to avoid taking the same ingredient twice. See a doctor if symptoms are severe, last longer than expected, or get worse, and straight away for a child with a high fever, breathing difficulty or signs of dehydration.
Buy from a source you can trust
Antibiotics that are fake, expired or badly stored may not work properly, which adds to the problem. Buy from a licensed pharmacy, check the label, and see how to spot fake or unregistered medicines.
Frequently asked questions
Can I take an antibiotic for a sore throat or cough?
Most sore throats and coughs are caused by viruses, and antibiotics do not help with them. Some throat infections are bacterial, so a doctor should decide if you need one.
What does "antibiotic resistance" mean?
It means bacteria have changed so that an antibiotic no longer works against them. Using antibiotics when they are not needed makes this more likely.
Can I buy antibiotics without a prescription?
Whether or not a shop will sell one, antibiotics are medicines that should be used on the advice of a doctor or pharmacist. Ask a professional before you take one.
Is a more expensive antibiotic better?
Not necessarily. The right antibiotic depends on the infection and the patient. Price or brand alone does not tell you that.
Sources and further reading
- World Health Organization, Antimicrobial resistance, fact sheet.
- The label and leaflet supplied with each medicine.
- DRAP, dra.gov.pk, for official information on registered medicines.
- Your doctor or pharmacist, for advice about your own health.