Fall brings the first colds of the season, and with them the cough that hangs on long after everything else has cleared. I was asked about exactly that for a Parade article on when to see a doctor about a persistent cough. This is the longer version of my answer, with the sources: how long a cough after a virus normally lasts, where the line is, the causes people rarely suspect, and what a proper workup looks like.

Coughing up more than a streak of blood, trouble breathing at rest, chest pain, or lips turning blue or gray are emergencies: call 911 or go to the emergency department.

How long a cough after a cold normally lasts

Doctors sort coughs by how long they have lasted, because the likely causes change with time.1

< 3 wksAcute: usually a cold, flu or COVID
3–8 wksSubacute: often the airways still healing
8+ wksChronic: look for another cause

After a virus, it is common for a cough to hang on for three to eight weeks while the airways heal. The infection is gone, but the lining of the airway stays inflamed and over-sensitive for a while, so cold air, talking or laughing can set off a coughing fit. A post-viral cough should be slowly getting better, even if it takes weeks.

There is no proven way to make it disappear faster. A Cochrane review found no good evidence for or against over-the-counter cough medicines,4 and honey has somewhat better support: a meta-analysis found it eased cough frequency and severity in upper respiratory infections compared with usual care.5 A spoonful on its own or in warm tea is a reasonable first step. Never give honey to a baby under one year old.

One exception is worth knowing. A cough that comes in violent fits, sometimes ending in a whoop, gagging or vomiting, can be pertussis (whooping cough), even in adults who were vaccinated as children. Get tested early, because treatment matters most for protecting infants and older relatives around you.

When to see a doctor about a cough

If a cough has lasted longer than eight weeks, it is no longer a leftover from a cold, and it deserves an evaluation. Do not wait that long if a cough is getting worse instead of better at three or four weeks, or if any of these come with it:1

  • Coughing up blood, even small streaks
  • Shortness of breath, especially at rest or at night
  • Fever, night sweats or weight loss you cannot explain
  • Hoarseness that does not clear, or trouble swallowing
  • Swelling in your legs with weight gain, which can point to the heart
  • Repeated bouts of pneumonia
  • A new or changed cough if you smoke or used to, particularly after 45

If breathlessness on exertion is the main thing you notice, my article on being winded on stairs covers how to tell fitness from a heart or lung problem.

The causes people do not suspect

In adults who do not smoke and have a normal chest X-ray, most chronic coughs come from a short list, and more than one can be at work at the same time.1,2

Medication

Blood pressure pills ending in “-pril”

ACE inhibitors such as lisinopril, enalapril, ramipril and benazepril cause a dry, tickly cough in roughly 5% to 35% of people who take them.3 The cough can start weeks or even months after you begin taking them, so nobody connects the two.

Practical read: the cough usually fades within one to four weeks of switching, though it can take up to three months. Do not stop a blood pressure medicine on your own.

Airways

Asthma, including cough-variant asthma

In cough-variant asthma the cough is the only symptom: no wheezing, no obvious shortness of breath. It is often worse at night, with exercise or in cold air. A related condition, non-asthmatic eosinophilic bronchitis, also responds to inhaled steroids.

Nose & Sinuses

Postnasal drip

Mucus draining from the nose and sinuses irritates the throat, from allergies, chronic rhinitis or sinusitis. Doctors call it upper airway cough syndrome. A constant need to clear your throat is a clue.

Stomach

Reflux, even without heartburn

Stomach contents reaching the throat can drive a cough with no heartburn at all. Late meals, alcohol and extra weight around the middle make it worse, and acid-suppressing medicine alone is often not enough.2

Smoking and vaping belong on the list too, and so do less common but serious causes: COPD, bronchiectasis, heart failure, lung scarring, tuberculosis and lung cancer. That is why a cough that will not quit gets a real look rather than another round of cough syrup.

If you are 50 to 80 and have smoked about a pack a day for 20 years or the equivalent, and still smoke or quit within the past 15 years, you qualify for a yearly low-dose CT scan to screen for lung cancer, cough or no cough.8 Far fewer eligible people get it than should.

What a chronic cough workup looks like

Treatment targets the cause, not the cough itself. So the job is to find the cause, in a sensible order:1,2

  1. History, medication review and exam

    When it started, what makes it worse, whether you smoke or vape, your home and work exposures, and every medicine on your list, especially for blood pressure. Stopping an ACE inhibitor (with your doctor switching you to another drug) comes first if you take one.

  2. A chest X-ray

    Looks for pneumonia, masses, fluid, an enlarged heart and lung scarring. If it is abnormal, or there are red flags, a CT scan is usually next.

  3. Breathing tests

    Spirometry before and after an inhaler shows asthma or COPD. When spirometry is normal but asthma is still suspected, a challenge test or an exhaled nitric oxide (FeNO) test can pick up airway inflammation.

  4. Targeted treatment trials

    If the tests point somewhere, treat that cause: nasal sprays for postnasal drip, inhaled steroids for asthma, and diet, meal timing and weight for reflux. Each trial needs enough time, often several weeks, before you judge it.

When no cause turns up

For stubborn cases with no clear cause, the problem is often the cough reflex itself. The nerves in the airway have become over-sensitive, so a breath of cold air or a few words of conversation sets them off. Specialists treat that directly, with two main tools:

  • Nerve-calming medication. In a randomized trial, gabapentin improved cough-related quality of life and cough frequency compared with placebo in people with refractory chronic cough.6 Pregabalin and low-dose morphine are other options in the European guideline.2
  • Cough-suppression therapy with a speech therapist. A few sessions teach you to recognize the urge early and break it with breathing and swallowing techniques. In a randomized trial it clearly outperformed a placebo program.7

Either way, a cough that has lasted months is not something to accept as your new normal.

Get to the cause

A chronic cough nearly always has an explanation, and finding it takes the same approach I use for everything else: the right history, the right tests in the right order, and a plan you can measure. If a cough has outlasted eight weeks, start with your own doctor. If you want an internist to work through it with you, that is what a free discovery call is for; read more about how we look for root causes.

Frequently asked questions

How long should a cough last after a cold?

A cough after a cold, flu or COVID commonly lasts one to three weeks, and it can linger for up to eight weeks while the airways heal. It should be gradually improving. A cough that is getting worse at three or four weeks, or that lasts longer than eight weeks, should be evaluated by a doctor.

When should I see a doctor about a cough that won't go away?

See a doctor if a cough lasts longer than eight weeks, if it is getting worse rather than better after three or four weeks, or sooner if it comes with coughing up blood, shortness of breath, fever, night sweats, unexplained weight loss, hoarseness, trouble swallowing or leg swelling. If you smoke or used to smoke, a new or changed cough deserves a prompt visit. Trouble breathing at rest, chest pain, or coughing up more than a streak of blood is an emergency.

Can blood pressure medicine cause a cough?

Yes. ACE inhibitors such as lisinopril, enalapril, ramipril and benazepril cause a dry, tickly cough in roughly 5% to 35% of people who take them. It can start weeks or even months after the first dose. The cough usually fades within one to four weeks of switching to a different medicine, though it can take up to three months. Do not stop a blood pressure medicine without talking to your doctor, who can switch you to an alternative.

What tests are done for a chronic cough?

A typical workup starts with a history, a medication review and an exam, then a chest X-ray and breathing tests (spirometry, sometimes with a challenge test or an exhaled nitric oxide test for asthma). A CT scan is used when the X-ray is abnormal or there are red flags. Treatment trials for postnasal drip, asthma or reflux are often part of finding the cause.

What helps a cough that won't go away?

For a cough after a virus, time is the main treatment; honey in warm water or tea can ease it, though it should never be given to babies under one. Over-the-counter cough medicines have little evidence behind them. For a chronic cough, treatment targets the cause, such as switching an ACE inhibitor, treating asthma, postnasal drip or reflux, or quitting smoking or vaping. When no cause is found, nerve-calming medications such as gabapentin and cough-suppression therapy with a speech therapist can help.

References

  1. Irwin RS, French CL, Chang AB, Altman KW; CHEST Expert Cough Panel. “Classification of Cough as a Symptom in Adults and Management Algorithms: CHEST Guideline and Expert Panel Report.” Chest 153, no. 1 (2018): 196–209. DOI: 10.1016/j.chest.2017.10.016

  2. Morice AH, Millqvist E, Bieksiene K, et al. “ERS guidelines on the diagnosis and treatment of chronic cough in adults and children.” European Respiratory Journal 55, no. 1 (2020): 1901136. DOI: 10.1183/13993003.01136-2019

  3. Dicpinigaitis PV. “Angiotensin-converting enzyme inhibitor-induced cough: ACCP evidence-based clinical practice guidelines.” Chest 129, no. 1 Suppl (2006): 169S–173S. DOI: 10.1378/chest.129.1_suppl.169S

  4. Smith SM, Schroeder K, Fahey T. “Over-the-counter (OTC) medications for acute cough in children and adults in community settings.” Cochrane Database of Systematic Reviews 2014, no. 11: CD001831. DOI: 10.1002/14651858.CD001831.pub5

  5. Abuelgasim H, Albury C, Lee J. “Effectiveness of honey for symptomatic relief in upper respiratory tract infections: a systematic review and meta-analysis.” BMJ Evidence-Based Medicine 26, no. 2 (2021): 57–64. DOI: 10.1136/bmjebm-2020-111336

  6. Ryan NM, Birring SS, Gibson PG. “Gabapentin for refractory chronic cough: a randomised, double-blind, placebo-controlled trial.” The Lancet 380, no. 9853 (2012): 1583–1589. DOI: 10.1016/S0140-6736(12)60776-4

  7. Vertigan AE, Theodoros DG, Gibson PG, Winkworth AL. “Efficacy of speech pathology management for chronic cough: a randomised placebo controlled trial of treatment efficacy.” Thorax 61, no. 12 (2006): 1065–1069. DOI: 10.1136/thx.2006.064337

  8. US Preventive Services Task Force. “Screening for Lung Cancer: US Preventive Services Task Force Recommendation Statement.” JAMA 325, no. 10 (2021): 962–970. DOI: 10.1001/jama.2021.1117

  9. Sardinha EL. “That Cough Has Been Hanging Around for Weeks—Here’s the Point When Doctors Want To Hear About It.” Parade, October 10, 2026. Quotes Dr. Luke Sorrell. parade.com