A cough is a protective reflex that helps clear mucus, irritants and other material from the throat and airways. Coughs may be dry or produce mucus. Many new coughs occur with respiratory infections, but a persistent or severe cough can have other causes and may need medical assessment.
Common causes
- Common cold, influenza, COVID-19 and other respiratory infections
- Acute bronchitis or pneumonia
- Asthma or COPD
- Allergies, sinus problems or mucus draining down the throat
- Gastroesophageal reflux disease (GERD)
- Smoking, secondhand smoke and other airway irritants
- Some medicines, including ACE inhibitors
Less common but important causes include tuberculosis, pulmonary embolism, heart disease and lung cancer. The cause cannot be determined from the sound of a cough alone.
How long can a cough last?
An acute cough often begins with a cold, flu or another respiratory infection and commonly improves within a few weeks. A cough can sometimes continue after the infection itself has improved because the airways remain irritated. A cough lasting more than eight weeks in an adult is generally considered chronic and should be assessed.
Self-care
- Drink enough fluids and rest when you are unwell.
- Avoid smoking, secondhand smoke and other irritants.
- A clean humidifier or moisture from a shower may soothe a dry throat for some people.
- Honey may help soothe cough in adults and children aged 12 months or older. Never give honey to a baby younger than one year.
Over-the-counter cough and cold medicines may reduce symptoms for some people but do not treat the underlying cause. Read labels carefully because combination products can contain the same active ingredients. Ask a healthcare professional or pharmacist before giving cough medicines to children or when you are pregnant, have other medical conditions or take prescription medicines.
Antibiotics
Antibiotics do not treat viral infections such as the common cold and are not routinely needed for an uncomplicated viral cough or acute bronchitis. They may be prescribed when a healthcare professional identifies or strongly suspects an appropriate bacterial infection.
When to seek medical advice
Contact a healthcare professional if a cough persists, repeatedly returns or is accompanied by fever that does not settle, wheezing, worsening shortness of breath, unexplained weight loss, night sweats or significant weakness. Medical assessment is also important for coughing up blood, possible tuberculosis exposure, or a new persistent cough in someone with important risk factors or chronic heart or lung disease.
Emergency warning signs
Seek emergency medical care for severe difficulty breathing, blue or gray lips or skin, confusion, collapse, severe or persistent chest pain, choking, or coughing up more than a small amount of blood. Use your local emergency medical service when symptoms are severe or life-threatening.
Related topics
See Shortness of Breath, Whooping Cough, Tuberculosis and Lungs and Airways.
Sources
Last reviewed: 4 September 2026. This page provides general health information and does not replace individual medical advice.