Do You Need Antibiotics? When They Help and When They Don’t

Many people expect antibiotics when they feel unwell, but most common illnesses, including colds, flu, COVID-19, most sore throats and most coughs, are caused by viruses and get better on their own. Antibiotics only help with bacterial infections. Taking them when they aren’t needed won’t speed up your recovery, and it can cause side effects and add to antibiotic resistance.

This guide explains how to tell when antibiotics are likely to help, when they usually aren’t needed, what you can do to feel better in the meantime, and the warning signs that mean you should see a doctor.

Bacterial or viral: why it matters

Bacteria and viruses both cause infections, but they’re very different. Antibiotics work by attacking parts of bacteria that viruses don’t have, so they have no effect on a viral illness. For a fuller explanation of how antibiotics work and why resistance develops, see our article Antibiotics and antibiotic resistance: how they work and how to use them safely.

It isn’t always possible to tell bacterial and viral infections apart from symptoms alone. Green or yellow mucus, for example, is common in viral colds and doesn’t on its own mean you need antibiotics. A doctor looks at the whole picture: how long you’ve been unwell, how severe your symptoms are, whether you’re getting better or worse, and your general health.

When you usually don’t need antibiotics

Antibiotics usually aren’t recommended for:

• Colds. A runny or blocked nose, sneezing and a sore throat usually ease within about 7 to 10 days.
• Flu and COVID-19. These are viral. Some people at higher risk of severe illness may be eligible for antiviral treatment, which is different from antibiotics. Read more about early assessment for COVID-19.
• Most sore throats. Most are viral and settle within about a week or so.
• Most coughs and chest colds (acute bronchitis). In otherwise healthy adults, these are usually viral. The cough often lasts 2 to 3 weeks and sometimes longer, even without anything serious going on.
• Most sinus infections. Sinusitis usually follows a cold and is usually viral.
• Many middle ear infections. These often get better on their own within a few days to a week.
• Most gastro. Vomiting and diarrhoea are usually viral and the main treatment is fluids. See our guide to gastroenteritis.

When antibiotics may be needed

A doctor may recommend antibiotics if a bacterial infection is likely and they’re expected to help. Examples include:

• most urinary tract infections (UTIs)
• some sore throats caused by bacteria, such as strep throat
• pneumonia caused by bacteria
• skin infections such as cellulitis or an infected wound
• some sexually transmitted infections, such as chlamydia and gonorrhoea
• sinus or ear infections that are severe, lasting a long time or causing complications, and ear infections in some higher-risk groups, such as very young children

Our article Common infections: which need antibiotics and which don’t goes through these conditions one by one.

What to expect from a GP consultation

When you see a GP with an infection, they’ll usually:

1. ask when your symptoms started and how they’ve changed
2. check for warning signs of a more serious illness
3. ask about your medical history, medicines and any allergies
4. suggest a test, such as a urine test, swab or blood test, if it would help confirm the cause
5. explain whether antibiotics are likely to help and what else you can do

Sometimes a doctor will suggest a “wait and see” approach. This means giving the illness a few days to settle, with a clear plan for what to do if you don’t improve or you get worse. This is a recognised, safe way to avoid unnecessary antibiotics. It isn’t a brush-off.

What helps while a viral illness runs its course

• Rest, and stay home from work or study while you’re unwell to avoid spreading the infection.
• Drink enough fluids to keep your urine pale.
• Use simple pain and fever relief if you need it. Your pharmacist can advise what suits you, especially if you take other medicines or have a health condition.
• Try warm drinks, honey (not for babies under 12 months) or saltwater gargles for a sore throat.
• Use saline nasal sprays or rinses for a blocked nose.
• Avoid smoking and second-hand smoke, which can make coughs last longer.

Pharmacists are a good first stop for advice about over-the-counter symptom relief. For more on the viruses that circulate through the colder months, see Common respiratory viruses.

When to see a GP

See a doctor if:

• your symptoms are severe, or you’re getting worse instead of better
• you seemed to be recovering, then got sick again
• a fever lasts more than a couple of days
• you have symptoms of a UTI, such as stinging when you wee
• a cough lasts more than 3 weeks, or you cough up blood
• you’re pregnant, older, or have a long-term condition or weakened immune system
• a baby or young child is unwell and you’re concerned

When to get urgent help

Call 000 or go to your nearest emergency department if you or someone you care for has:

• difficulty breathing, or chest pain
• blue or grey lips, or cold, clammy skin
• confusion, drowsiness, or is hard to wake
• a stiff neck, a rash that doesn’t fade when pressed, or severe headache with fever
• trouble swallowing, drooling, or can’t keep fluids down
• signs of a severe allergic reaction, such as swelling of the face or tongue

How Teldoc can help

Our AHPRA-registered GPs can assess common infections by phone or video, 7 days a week from 9 am to 7 pm (Sydney time). Most patients are seen within 15 minutes. Your doctor can explain whether antibiotics are likely to help, prescribe treatment if clinically appropriate with an eScript sent to your phone, arrange tests if needed, provide a medical certificate if you’re too unwell to work or study, and tell you if you need to be examined in person.

General consultations are $55 on weekdays and $75 on weekends and public holidays, with no Medicare rebate. See our fees page for details, or read about cold and flu consultations and antibiotic prescriptions.

Frequently asked questions

Do I need antibiotics for a cold or flu?

No. Colds and flu are caused by viruses, and antibiotics don’t work against viruses. Rest, fluids and symptom relief are usually all that’s needed, but see a doctor if you’re getting worse or have warning signs.

Does green mucus mean I need antibiotics?

Not necessarily. Green or yellow mucus is common with viral colds and doesn’t on its own mean you have a bacterial infection. A doctor will consider how long you’ve been unwell and how severe your symptoms are.

Why didn’t my doctor prescribe antibiotics?

If your illness is likely to be viral or to get better on its own, antibiotics won’t help and can cause side effects. Your doctor may suggest a wait-and-see approach with a plan for what to do if you don’t improve.

How long should a cough last?

A cough after a cold or chest infection often lasts 2 to 3 weeks and sometimes longer. See a doctor if it lasts more than 3 weeks, you’re short of breath, you have a high fever or you cough up blood.

Can a telehealth doctor prescribe antibiotics?

Yes, if they’re clinically appropriate. A telehealth GP can assess many common infections by phone or video and send an eScript to your phone, and will tell you if you need a test or an in-person examination.

Sources and further reading: healthdirect: Antibiotics; healthdirect: Medicines for colds, flu and COVID-19; healthdirect: Urinary tract infection (UTI).

This article is general health information and isn’t a substitute for advice from your own doctor. If you’re worried about your health, speak to a GP. In an emergency, call 000.

Medically reviewed by Dr Vafa Derakshan (MBBS, FRACGP), September 2026