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Foul-smelling Cough: Symptoms & Causes

An illustration of two people side by side from the waist up. The woman on the left has medium peach-toned skin and blue curly hair and is covering her open mouth with her left hand. Blue lines and squiggles come out of her mouth. She is wearing a yellow short-sleeved t-shirt. The man on the right is covering his mouth and nose, he has the same skin tone as the woman and has short, curly, red hair. He is wearing a dark blue turtleneck short-sleeved shirt. The background is a light yellow rectangle at the bottom of the image up to just under their shoulders.
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Written by Andrew Le, MD.
Medically reviewed by
Clinical Physician Assistant, Summit Health
Last updated April 10, 2024

Foul-smelling cough quiz

Take a quiz to find out what's causing your foul-smelling cough.

Experiencing a bad taste in your mouth after coughing could simply be bad breath. However, it could also point to an underlying condition. Causes for bad taste from coughing range in severity. Read more below to learn 3 possible causes of bad tasting cough.

4 most common cause(s)

Lung Abscess
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Foul-smelling cough quiz

Take a quiz to find out what's causing your foul-smelling cough.

Take foul-smelling cough quiz

3 causes of a foul-smelling cough

The list below shows results from the use of our quiz by Buoy users who experienced foul-smelling cough. This list does not constitute medical advice and may not accurately represent what you have.

Lung abscess

An abscess is a collection of pus which results from an infection. A lung abscess may form following an infection such as pneumonia.

You should visit your primary care physician within the next 24 hours. Your doctor will confirm the diagnosis with an X-Ray. Treatment for a lung abscess involves prescription antibiotics.

Chronic obstructive pulmonary disease (COPD)

Chronic obstructive pulmonary disease (COPD) is a progressive inflammation of the lungs that makes breathing difficult. It is caused by long-term exposure to irritating gases and/or dust particles, most often cigarette smoke.

Symptoms may take years to develop. They include a chronic cough with mucus (sputum), wheezing, chest tightness, fatigue, constant colds, swollen ankles, and cyanosis (blue tinge to the lips and/or fingernails.) Depression is often a factor due to reduced quality of life.

Treatment is important because there is a greater risk of heart disease and lung cancer in COPD patients. Though the condition cannot be cured, it can be managed to reduce risks and allow good quality of life.

COPD is commonly misdiagnosed and so careful testing is done. Diagnosis is made through patient history; physical examination; lung function tests; blood tests; and chest x-ray or CT scan.

Treatment involves quitting smoking and avoiding exposure to other lung irritants; use of inhalers to ease symptoms; steroids; lung therapies; and getting influenza and pneumonia vaccines as recommended.


Bronchiectasis is destruction and widening of the large airways. Mucus builds up in these airways and can get infected, causing a pneumonia.

You should visit your primary care physician within the next 24 hours if you might have an infection. Diagnosis involves a chest X-ray, sampling phlegm, blood tests, and other possible tests. Treatment is mostly coaching, actually, on exercises that strengthen your ability to cough up phlegm.

Rarity: Rare

Top Symptoms: cough, shortness of breath, wheezing, runny nose, mucous dripping in the back of the throat

Urgency: Primary care docto

Bacterial pneumonia

Bacterial pneumonia is an infection of the lungs caused by one of several different bacteria, often Streptococcus pneumoniae. Pneumonia is often contracted in hospitals or nursing homes.

Symptoms include fatigue, fever, chills, painful and difficult breathing, and cough that brings up mucus. Elderly patients may have low body temperature and confusion.

Pneumonia can be a medical emergency for very young children or those over age 65, as well as anyone with a weakened immune system or a chronic heart or lung condition.

Complications may include organ failure and respiratory failure. Take the patient to the emergency room or call 9-1-1.

Diagnosis is made through blood tests and chest x-ray.

With bacterial pneumonia, the treatment is antibiotics. Be sure to finish all the medication, even if you start to feel better. Hospitalization may be necessary for higher-risk cases.

Some types of bacterial pneumonia can be prevented through vaccination. Flu shots help, too, by preventing another illness from taking hold. Keep the immune system healthy through good diet and sleep habits, not smoking, and frequent handwashing.

Rarity: Common

Top Symptoms: fatigue, cough, headache, loss of appetite, shortness of breath

Symptoms that always occur with bacterial pneumonia: cough

Urgency: In-person visit

Questions your doctor may ask about foul-smelling cough

To diagnose this condition, your doctor would likely ask the following questions:

  • Any fever today or during the last week?
  • Have you experienced any nausea?
  • Do you currently smoke?
  • Have you been feeling more tired than usual, lethargic or fatigued despite sleeping a normal amount?

Self-diagnose with our free Buoy Assistant if you answer yes on any of these questions.

Foul-smelling cough symptom checker statistics

People who have experienced foulsmelling cough have also experienced:

  • 13% Cough
  • 4% Chronically Bad Breath
  • 3% Vaginal Discharge

People who have experienced foulsmelling cough were most often matched with:

  • 35% Bacterial Pneumonia
  • 35% Lung Abscess
  • 28% Bronchiectasis

People who have experienced foulsmelling cough had symptoms persist for:

  • 43% Less than a week
  • 15% One to two weeks
  • 15% Two weeks to a month

Source: Aggregated and anonymized results from Buoy Assistant.

Hear what 5 others are saying
Once your story receives approval from our editors, it will exist on Buoy as a helpful resource for others who may experience something similar.
The stories shared below are not written by Buoy employees. Buoy does not endorse any of the information in these stories. Whenever you have questions or concerns about a medical condition, you should always contact your doctor or a healthcare provider.
DamnPosted January 8, 2022 by C.
When I blow my nose or cough i taste and smell something rotten. I Was told 3or4 months ago I had a spot on my lungs don't have any insurance my teeth are ok
Bad taste when I coughPosted February 4, 2021 by D.
I have recently changed my diet and eat lots of vegetables and fruits, I also started running once or twice every couple weeks. I haven't smoked in several months. I noticed a significant cough after running in the cold and lots of clear phlegm. Possibly unrelated has been this nasty taste in my mouth that I cannot cover up. I admit I forgot to do my oral routine before bed a couple times, but this has never occurred in the past because of any aforementioned. This is like a bad cardboard taste or almost rotten moldy broccoli taste deeper/past than the tonsils it seems. It's not a comforting feeling, it just seems off. It's been two days, now. Last month it occurred for about two to three days.
Chemical taste phlegmPosted November 6, 2020 by D.
I have Stage 4 COPD with a persistent cough, especially at night. I still smoke, which at times actually soothes the cough. I have been through the rainbow with the phlegm in the past two months—started out green, then yellow, then brownish, now very thick and white. When I start coughing my nose also becomes a fountain. But just in the past two weeks, I have noticed a chemical taste to the phlegm. Is it just me or is there something seriously wrong?
Clinical Physician Assistant, Summit Health
Jeff brings to Buoy 20 years of clinical experience as a physician assistant in urgent care and internal medicine. He also has extensive experience in healthcare administration, most recently as developer and director of an urgent care center. While completing his doctorate in Health Sciences at A.T. Still University, Jeff studied population health, healthcare systems, and evidence-based medicine....
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