Toux
Revu par Dr Colin Tidy, MRCGPDernière mise à jour par Dr Philippa Vincent, MRCGPDernière mise à jour 23 mars 2023
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Dans cette série :Rhume communToux viraleToux et rhumes chez les enfantsToux chronique persistante chez les adultesToux avec du sangMédicaments contre la toux
A cough is a common reflex that your body does to help clear your airways of mucus, irritants, or infections. Most coughs are caused by a cold, flu, or mild respiratory infections and often last 3-4 weeks.
This leaflet explains the what causes a cough and how to help stop it.
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Points clés
A cough is a natural reflex that clears mucus, irritants, or germs from the airways, helping to protect the lungs.
Most coughs are usually caused by colds, flu, or mild respiratory infections. Persistent coughs may be linked to asthma, allergies, smoking, acid reflux, or chronic lung conditions.
See a doctor if a cough lasts longer than 3 weeks, you cough up blood, or comes with chest pain, breathing difficulties, or unexplained weight loss.
Most coughs improve on their own and can be managed by staying hydrated, resting, avoiding smoking, and using over-the-counter remedies.
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What is a cough?
A cough is an automatic (reflex) muscle action that forces air up and out of your lower airways (lungs) and upper airways (windpipe, nose and mouth). Everyone coughs occasionally to 'clear their throat'. The cough reflex protects the airways and lungs.
Coughing occurs if the airways are partially blocked by mucus (for example, during a cold). It also occurs when choking on a piece of food which enters the windpipe (trachea) instead of going down the food pipe (oesophagus). People may need to cough if they breathe in chemicals or smoke that irritates the airways.
Doctors divide cough symptoms as follows:
Acute, meaning it lasts for less than three weeks.
Subacute, meaning it lasts for three to eight weeks.
Chronic, meaning it lasts for longer than eight weeks.
Acute cough usually improves after one week although often lasts for up to three. The most common cause is a viral infection which causes a runny nose and cough. Viral infections can affect anyone. Young children commonly have eight viral infections a year, especially in the winter months and these are usually associated with a high temperature (fever). With each episode lasting 7-21 days, it can feel as though they are unwell more often than they are well. It is important to remember that each episode increases the immunity of that child and usually no treatment is required.
Chronic cough is common. 1-2 adults in 10 are affected.
What causes a cough?
Retour au sommaireCommon causes of acute cough (lasting less than three weeks)
Upper respiratory tract infections. These are the most common cause of acute coughs. They are caused by infection with a germ (virus). They usually start to improve within a week, without specific treatment. Symptoms may go on for up to three weeks.
Lower respiratory tract infections. These are less common and cause lung infections such as bronchite ou pneumonie. These conditions may be caused by infection with germs (viruses, bacteria or fungi).
Asthme. This causes wheeze, breathlessness and cough which tends to be worse at night, in cold air and during exercise. An infection with a virus can make symptoms of asthma much worse. This is called an exacerbation of asthma.
Irritants - smoke or chemical fumes that you breathe in may irritate the airways.
Common causes of subacute cough (lasting three to eight weeks)
Airways that are slow to settle down after an infection. In this case the germ has gone but the airways are still swollen and irritable, causing an ongoing cough. This is called airway hyper-responsiveness.
Other infections which may cause a longer-lasting cough, such as tuberculosis (TB).
Common causes of chronic cough (lasting more than eight weeks)
Postnasal drip. This is a condition where mucus in the nose drips down the back of the throat. It can be caused by anything which causes the nose to produce more mucus. This includes allergies, rhume des foins et les polypes nasaux as well as viral infections.
Reflux acide. Acid in the stomach washes up the food pipe and spills into the airways.
Asthma. Undiagnosed or under-treated asthma causes cough.
Side-effects of medication. For example, médicaments inhibiteurs de l'enzyme de conversion de l'angiotensine (ECA), which are used to treat l'hypertension artérielle, can cause cough.
Lung disease caused by smoking - chronic obstructive pulmonary disease (COPD). The lung damage causes cough and breathlessness to get steadily worse. This mainly affects smokers.
Irritants such as cigarette smoke including being in contact with other people's smoke (passive smoking).
Less common causes of cough
A foreign body. Food can go down the windpipe instead of the food pipe. Other objects may also be inhaled by accident, such as beads, particularly in children.
Cancer du poumon. This is more likely in smokers.
Mucoviscidose. This is an inherited condition that affects the lungs and causes chronic cough.
Pneumothorax. In this condition, air gets trapped outside the lung, inside the chest.
Bronchectasie. This is a condition where airways of the lungs are excessively widened and produce extra mucus.
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How to stop a cough
Retour au sommaireTreatment will depend on the likely cause of the cough.
For acute coughs due to viral infections, nothing will stop or get rid of the cough which will settle with time. However some simple remedies can help reduce the symptoms:
Inhaling steam, or honey and lemon to soothe the throat.
Reducing a temperature or soothing aches and pains with paracétamol ou ibuprofène.
Using asthma inhalers if these have been prescribed for asthma
For coughs due to lower respiratory tract infections, if a bacterial cause is suspected, antibiotics might be prescribed.
Coughs should not usually be treated with antibiotics. The vast majority of coughs are caused by viruses - antibiotics have no effect on viruses and can cause vomiting, diarrhoea, anaphylaxis and many other side effects. The National Institute for Health and Care Excellence (NICE) guidelines advise that people with viral upper respiratory tract infections and people with bronchitis should not generally be given antibiotics.
People who are at risk of bacterial infections (see below*) should be assessed to see if they need antibiotics. It is a myth that the colour of the phlegm can predict whether a cough has a bacterial or viral cause - almost all coughs producing phlegm are viral.
People with confirmed chronic obstructive pulmonary disease (COPD) which is usually a smoking-related illness are more prone to getting bacterial lung infections. They will usually be prescribed antibiotics to take when they have early signs of one of these infections.
For more chronic coughs, these remedies may help:
Switching to another type of high blood pressure tablets if this is the cause of the cough.
Using a steroid nasal spray to help postnasal drip.
Perdre du poids, cutting out acid foods and alcohol.
Prendre medicine to stop acid in the stomach may all help acid reflux.
With a chronic cough, a referral to a lung (respiratory) specialist might be advised in order for further tests to be carried out. Most coughs will be managed by a GP without the need for this.
* At-risk groups include people with existing heart, lung, kidney, liver or nervous system disease; cystic fibrosis or conditions affecting the immune system; young children who were born prematurely; over-65s who have a combination of two or more of diabète, being in hospital in the previous year, une insuffisance cardiaque or are taking steroids; or over-80s who have one of these factors.
When do I need a chest X-Ray if I have a cough?
What should I do if I develop a cough?
Retour au sommaireThis will depend on how long the cough has lasted and how unwell you are feeling. If you feel well and the cough has not lasted long, you do not need to do anything but wait for it to settle. Simple remedies as described above may help while you wait for it to go on its own.
You should contact your GP if your cough lasts more than three weeks and is not improving. See your GP urgently if you feel very unwell, or if you develop red flag symptoms (see above). Use your reliever inhaler as instructed if you have asthma.
You should call an ambulance (999/112/911) if you experience unexpected and severe cough and difficulty in breathing that lasts for more than a few minutes. Otherwise, you should call your GP if concerned.
Potentially concerning causes of cough
Seek medical help urgently if:
You are short of breath with your cough.
You have chest pain with your cough (particularly if this is on one side and worse on breathing in.
You are coughing up blood.
Your cough has persisted for longer than three weeks and is not improving.
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What investigations may be advised?
Retour au sommaireThe doctor will want to know how long the cough has lasted and whether there are any other symptoms. The doctor will particularly ask about symptoms which may suggest an underlying serious condition ('red flags').
Red flag symptoms that may suggest serious underlying disease:
A doctor will want to know:
Did it start suddenly or develop over time? Did anything trigger it? How long has it lasted?
When do you cough? Is it worse when you exercise?
Are you breathless even when you're not coughing?
Have you got any pain in your chest?
Are you coughing up anything? What colour is it? Is there any blood?
Do you feel ill? Do you have weight loss or sweats?
Have you been in contact with anyone with TB or travelled abroad recently?
Do you smoke?
What is your occupation?
Have you started any new medication recently?
These details will help the doctor to make a diagnosis. They will usually examine the throat, lungs and heart and may request some lung function tests, including a blowing test called a peak flow reading. Another blowing test (sometimes available in a GP surgery but sometimes requiring a referral) is called spirometry. Une radiographie thoracique may be requested. Further tests of your lungs may be necessary depending on the results.
How long does a cough last?
Retour au sommaireThis depends on the underlying cause. Most acute coughs will start to improve within a week and the cough will usually disappear within three weeks. People with smoking-related diseases tend to be affected by coughing and breathlessness. These smoking-related diseases tend to get worse as time goes on.
How can I avoid coughing?
Retour au sommaireYou will need to find the underlying cause and try to address it if possible. Don't smoke, or get help to stop smoking, because all common serious causes of chronic cough are more likely to affect smokers. Try to avoid dusty or smoky places. Use your asthma medication as advised.
Most over-the-counter cough medicines are not very effective. Sipping fluids, sucking lozenges or drinking warm drinks (for example, lemon with honey) can help a little but coughs are a vital reflex and cannot be stopped altogether. Products that contain codéine may help to stop coughing but often have unwanted side-effects like constipation and drowsiness.
Questions fréquemment posées
Retour au sommaireWhy does my head hurt when I cough?
Head pain when coughing is usually due to an increase in pressure inside the head and is often caused by colds, flu, or sinus issues. It’s usually harmless, but see a doctor if it’s severe, persistent, or frequent.
Why is my cough worse at night?
A cough often feels worse at night because lying down lets mucus pool in the throat, causing irritation. Post-nasal drip, reflux, or asthma can add to this. Sleeping propped up and treating underlying causes may help ease symptoms.
Why is my cough not stopping?
A cough that won’t stop may be due to infection, asthma, reflux, allergies, smoking, or medicines. See a doctor if it lasts over three weeks or causes concern.
Can hay fever make you cough?
Yes, hay fever can make you cough. Allergies cause irritation in the nose and throat, and post-nasal drip (when mucus runs down the back of your throat) can trigger a tickly or persistent cough. It is usually harmless.
Sélections de patients pour Toux

Poitrine et poumons
Toux chronique persistante chez les adultes
A cough is termed "chronic" when it becomes persisting and long-term. This typically means it has hung around for more than eight weeks. Other types of cough such as a shorter-term cough, lasting up to three weeks, is called "acute", and if it is somewhere in the middle, it's called "subacute". Infections (such as the common cold or a chest infection) are the most common reason for acute coughs, but these usually settle within about three weeks. See also the leaflet on Cough.
par Dr Colin Tidy, MRCGP

Poitrine et poumons
Toux avec du sang
There are various causes of coughing up blood (haemoptysis). If you cough up a lot of blood then call for an ambulance immediately. If you cough up smaller amounts of blood then see your doctor as soon as possible if you do not know the cause. This is because sometimes a serious condition such as cancer of the lung can be the cause. As a general rule, the earlier a serious problem is diagnosed, the better the chance that treatment may improve the outlook (prognosis). This leaflet discusses the main causes of coughing up blood.
par Dr Hayley Willacy, FRCGP
Lectures complémentaires et références
- Toux; NICE CKS, April 2025 (UK access only).
- Recommendations for the assessment and management of cough in children; British Thoracic Society Cough Guideline Group - BMJ (2008)
- Médicaments contre la toux et le rhume en vente libre pour enfants; Agence de Régulation des Médicaments et Produits de Santé (MHRA), 2014
- Toux (aiguë) : prescription d'antimicrobiens; Recommandations NICE (février 2019)
- Morice AH, Millqvist E, Bieksiene K, et al; Directives de l'ERS sur le diagnostic et le traitement de la toux chronique chez les adultes et les enfants. Eur Respir J. 2 janv. 2020;55(1). pii: 13993003.01136-2019. doi: 10.1183/13993003.01136-2019. Imprimé en janv. 2020.
- Gruffydd-Jones K; Managing Cough in Primary Care; Primary Care Respiratory Update
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Historique de l'article
Les informations sur cette page sont rédigées et examinées par des cliniciens qualifiés.
Prochaine révision prévue : 21 mars 2028
23 mars 2023 | Dernière version
14 Jan 2013 | Publié à l'origine
Écrit par :
Dr Ann Robinson, MRCGP

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