Antibiotics don't work on colds and flu

Taking antibiotics for colds and flu? There's no point.
Colds and flu are caused by a virus and antibiotics do not work on viruses.

What are antibiotics?

Antibiotics are medicines used to treat infections caused by bacteria. Antibiotics don't work against infections caused by viruses, such as colds and flu. So there's no point taking antibiotics to treat a cold or flu, and no point asking your doctor to prescribe them for a cold or flu.

Taking antibiotics when you don't need them, like for a cold or flu, is a waste. It can also mean that they won't work when you really need them for a serious infection. This is called antibiotic resistance and it happens when bacteria are exposed to antibiotics and learn to resist them. Taking antibiotics when they are not needed also puts you at risk of side effects, like a rash, upset stomach or diarrhoea.

When are antibiotics not needed?

Most common infections are caused by viruses. Antibiotics do not work against viruses. Most viral illnesses get better themselves without antibiotics. The table below helps you to know when you're likely to need an antibiotic - and when you aren't.

Know when we need antibiotics - and when we don't
Common Cause: Virus Common Cause: Bacteria

Head cold, runny nose, cough

Sore throat, sinusitis

Ear infections in children

Vomiting and diarrhoea

Urine / kidney infection

Persisting cough, cough in people with chest problems, high fever or very unwell

Skin infections e.g. cellulitis


Antibiotics rarely needed Antibiotics may be needed


When is it OK for me or my child to take antibiotics?

Your doctor may prescribe antibiotics for infections that are caused by bacteria, like some chest infections, kidney infection, some ear infections and meningitis.

If you or your child needs antibiotics, make sure you take them exactly as prescribed. If the course isn't completed, some bacteria may be left in your body and become resistant to antibiotics. Never keep or re-use left over antibiotics for the next time you, your child, or any other family member is sick.

Why didn't my doctor prescribe an antibiotic?

It is because your infection is likely caused by a virus and it's safer to let it clear up on its own. Remember, antibiotics are no use against a virus. The length of time you can expect most common infections to last is:

Ear infection: around 4 days
Sore throat: around 1 week
Common cold (runny nose): around 1½ weeks
Sinus infection: around 2½ weeks
Cough (which often happens after a common cold):
around 3 weeks

If your illness lasts longer than this, ask your doctor or pharmacist for advice.

You can also visit our new Health A-Z - it contains information and advice on how to treat and recover from a wide range of common illnesses.

Ask your doctor or pharmacist:

  • When should I start to feel better?
  • What should I do if I don't start to feel better by then?
  • Is there anything I can do to help myself get better?
  • When and how should I seek further help?
  • How should I treat a cold, cough or sore throat?

The best way to treat most colds, coughs or sore throats is to drink plenty of fluids and get some rest. Ask your pharmacist for advice about over-the-counter remedies, and read the table below for information on how to treat some common symptoms.

Symptoms Treatment
Runny nose, blocked nose or congestion

Nasal decongestant spray, oral decongestant syrup or tablets.

Menthol & eucalyptus oil preparations.

Sore throat

Honey & lemon, anaesthetic lozenges.

Paracetamol or ibuprofen.

Cough in an adult

Antitussive for dry cough - to stop you coughing.

Mucolytic or expectorant for chesty cough - to help you break up mucus.

Fever, pain, joint or muscle aches Paracetamol or ibuprofen
Cough in a child Discuss with your doctor
or pharmacist.

If you are taking medicines for any other conditions, you must check with your doctor or pharmacist before you take any over-the-counter remedies.

Why should we be concerned about antibiotic resistance?

Taking antibiotics when they aren’t needed might mean that they won’t work when you really need them for a serious infection. If you take many courses of antibiotics, bacteria can change so that the antibiotic does not work against them any more. These bacteria are said to be “resistant” to this antibiotic and are much harder to treat.

If you get an infection caused by bacteria that are resistant to antibiotics, your infection can last longer. You might have to be treated in hospital.  At the same time, your family members or other people you come in contact with may catch the resistant bacteria that you have. Then these people might also get infections that are hard to cure.

From a wider perspective we are running out of antibiotics that are resistant to bacteria – if we lose this war against antibiotic resistance it could set medicine back decades.

What else can I do to reduce the risk of antibiotic resistance?

Wash hands with soap and water before eating and after using the toilet. Regular hand washing helps keep you healthy and prevent the spread of bacteria.

Ask your doctor if you have all the vaccinations you need to protect yourself from infection. If you have young children, make sure they are up to date with their childhood immunisations.

Key things to remember

  • Most common infections get better by themselves - without antibiotics
  • Taking antibiotics when you don't need them can put your health, and the health of your family, at risk
  • If your doctor decides that you need an antibiotic, be sure you take it exactly as prescribed
  • Your pharmacist can advise you on over-the-counter remedies that can help to treat many common infections