Repeated spitting up of mucus is commonly caused by postnasal drip, allergies, infection, acid reflux, or smoking. See a doctor if it persists or has blood.
Common causes
- Postnasal drip.
- Allergies.
- Cold or sinus infection.
- Acid reflux.
- Smoking.
- Bronchitis.
- Dehydration.
What helps
- Drink water.
- Saline spray.
- Humidifier.
- Treat reflux or allergies.
Normal
The body makes 1 to 1.5 liters of mucus a day.
See a doctor
If there is blood, fever or symptoms for over 3 weeks.
Where mucus comes from
The airways and sinuses make 1 to 1.5 liters of mucus per day, most of which is swallowed unnoticed. Spitting mucus often relates to postnasal drip from allergies or colds, acid reflux, smoking, dehydration, asthma or chronic bronchitis.
- Clear or white mucus is common with allergies and colds. Yellow or green indicates immune cells but does not alone prove bacteria.
- Chronic bronchitis and COPD cause daily mucus for 3 months in each of 2 years.
- Dairy does not increase mucus production according to controlled studies, although milk can feel thicker in the mouth.
Care and when to see a doctor
Drink fluids, use saline nasal rinses with distilled water, run a humidifier and avoid smoke. Treat reflux with dietary changes and elevate the head of the bed. Seek care for blood in mucus, fever, shortness of breath, symptoms over 3 weeks, or unexplained weight loss. Smokers with persistent mucus cough should ask about lung screening if eligible (age 50 to 80 with a 20 pack-year history).
Where mucus comes from
The nose, sinuses and throat produce about 1 to 1.5 liters of mucus per day. Postnasal drip from allergies or colds, reflux, smoking and dry air can cause extra mucus in the throat that people spit up.
Care and when to see a doctor
Hydrate, use saline rinses, treat allergies and reflux. See a doctor if mucus has blood, persistent for weeks, or comes with fever, weight loss or shortness of breath.
Mucus production and conditions
The respiratory tract has goblet cells that secrete mucus, and cilia move it up for swallowing. Smoking, allergies, GERD, chronic bronchitis, sinusitis and dehydration increase thick mucus. Dairy does not increase mucus production per controlled studies, though it can change texture feeling.
Home care and testing
Drink water, use a humidifier, try saline nasal irrigation and treat reflux. Guaifenesin helps thin secretions in some people. See a doctor if mucus is bloody, persistent beyond 3 weeks or comes with weight loss, wheeze or fever. Tests may include chest X ray and sputum culture. Smokers with chronic morning mucus may have COPD.
Based on data from the American Lung Association and the Mayo Clinic
