Mouth Breathing: Causes, Symptoms, Treatment and Prevention
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick Answer: What is mouth breathing?
Mouth breathing is frequent breathing through the mouth instead of the nose, often because congestion, allergies, a deviated septum, enlarged adenoids or tonsils, nasal polyps or sleep apnea make nasal airflow difficult. Persistent mouth breathing can cause dry mouth, bad breath, snoring and tiredness. A healthcare provider can examine the nose and throat and treat the underlying cause.
What the research says
In children with snoring and mild sleep-disordered breathing, early adenotonsillectomy was linked to less health care use. In the Pediatric Adenotonsillectomy Trial for Snoring (459 children randomized; 381 analyzed; ages 3–13), adenotonsillectomy was associated with a 32% reduction in total health care encounters (mean difference −1.25 per participant per year; 95% CI −1.96 to −0.53) and a 48% reduction in prescriptions (mean difference −2.53; 95% CI −4.12 to −0.94) over 12 months compared with watchful waiting with supportive care (Bakker et al., JAMA Pediatr, 2025). [2]
Snoring-related symptom burden and quality-of-life problems tracked with executive-function difficulties in children. In a cross-sectional analysis of 459 children with mild sleep-disordered breathing, a global executive-function score was moderately correlated with the sleep-related breathing symptom scale (r = 0.58; 95% CI 0.51–0.64) and with an obstructive sleep apnea quality-of-life score (r = 0.59; 95% CI 0.52–0.64); this shows an association, not cause and effect (Yu et al., JAMA Otolaryngol Head Neck Surg, 2025). [3]
What is mouth breathing?
Mouth breathing occurs when a person frequently draws air through the mouth instead of the nose. Nasal breathing is usually the body’s normal route for moving air, but a person may switch to mouth breathing when the nose is blocked or airflow is restricted.
Breathing through the mouth while running or catching your breath can be normal. The concern is persistent mouth breathing, especially when it becomes the only comfortable way to breathe or continues during sleep.
Mouth breathing in adults is generally not a serious health issue by itself. In children, however, ongoing mouth breathing can affect growth and behavior and may change the shape of the face.
What are the symptoms of mouth breathing?
Mouth breathing can affect both children and adults, and common signs include bad breath, drooling during sleep, dry mouth, tiredness, hoarseness and snoring. Common signs include:
Bad breath.
Drooling while asleep.
Dry mouth.
Feeling tired much of the time.
Hoarseness.
Snoring.
A person may not realize they are mouth breathing, particularly during sleep. Waking with a dry mouth, noticing drool on the pillow or hearing about nighttime snoring can provide a clue.
Symptom | What it may look like |
Dry mouth | Waking with a parched mouth or needing water often at night. |
Bad breath | Persistent morning breath or an odor that may be related to reduced moisture in the mouth. |
Drooling during sleep | Saliva on the pillow or bedding. |
Snoring | Noisy breathing during sleep. |
Hoarseness | A rough or strained voice. |
Tiredness | Feeling fatigued, particularly when sleep is restless. |
These signs do not identify a single cause. A clinician can look for nasal blockage, sleep-related breathing problems or another explanation.
What are the signs in children?
Children may show the general symptoms above as well as changes related to sleep, facial development and behavior.
Mouth-breathing facial pattern
Persistent breathing through the mouth instead of the nose can change the shape of a child’s face. The face may appear narrow, the chin or jaw may recede, and the upper and lower teeth may not line up.
This pattern is not something a child is choosing deliberately. It may reflect difficulty moving air through the nose or another airway problem that needs evaluation.
Growth concerns
Mouth breathing is not directly responsible for growth problems. However, a child may mouth-breathe because something blocks the airway, such as enlarged adenoids. Airway problems may affect the pituitary gland’s release of human growth hormone, which can affect growth.
A child’s growth should be assessed in context by a pediatrician or another qualified clinician. Do not assume that mouth breathing alone explains a change in height or weight.
Behavior and sleep changes
Some children who mouth-breathe may also have sleep apnea or another sleep problem. Poor sleep can contribute to irritability and restlessness and may produce behavior patterns similar to those seen in attention-deficit/hyperactivity disorder (ADHD).
Mouth breathing does not prove that a child has ADHD or sleep apnea. Snoring, restless sleep and daytime behavior changes are reasons to discuss the child’s breathing and sleep with a pediatrician.
Why do people breathe through their mouths?
Most people mouth-breathe because air cannot move easily through the nose. The blockage may be temporary, such as during a cold, or ongoing, such as with a deviated septum or nasal polyps.
Possible cause | How it can affect nasal breathing |
Deviated septum | The cartilage and bone dividing the inside of the nose lean to one side and can narrow the airway. |
Enlarged turbinates | Turbinates help moisten and clean inhaled air. Allergies, infections or irritation can swell them and make nasal breathing harder. |
Enlarged adenoids or tonsils | Swollen or infected tissue can block the airway, especially in children. |
Nasal congestion | Allergies, colds and chronic sinusitis can clog the nose. |
Nasal polyps | Swollen or irritated growths can make it difficult for air to pass through the nose. |
Sleep apnea | Repeated pauses in breathing during sleep can prevent restful sleep and may occur alongside mouth breathing. |
Deviated septum
The septum is cartilage and bone that divides the inside of the nose. When it leans to one side, it can narrow one nasal passage and make it harder to breathe through the nose.
Enlarged turbinates
Turbinates are structures inside the nose that help moisten and clean the air. Allergies, infections and irritation can make the lower turbinates swell. Swelling may reduce the space available for airflow.
Enlarged adenoids or tonsils
In children, swollen or infected adenoids or tonsils can block the airway. A child may then breathe through the mouth, snore or sleep restlessly.
Nasal congestion
Allergies, colds and chronic sinusitis can clog the nose. When air cannot move well through the nose, mouth breathing may become the easier route.
Nasal polyps
Nasal polyps are growths inside the nose. If they become swollen or irritated, they may make it hard for air to pass through the nasal passages.
Sleep apnea
Sleep apnea causes a person to stop breathing while asleep. Those interruptions prevent restful sleep and can occur with snoring, mouth breathing and daytime tiredness. [1]
Is mouth breathing a serious problem?
The importance of mouth breathing depends on the person, how often it happens and what is causing it. In adults, mouth breathing by itself generally is not a serious health issue. Persistent symptoms may still deserve evaluation because they can reflect nasal blockage or sleep-related breathing problems.
In children, ongoing mouth breathing may affect behavior, sleep, growth and facial shape. A child who often breathes through the mouth should have the nose and airway assessed by a pediatrician or another qualified healthcare provider.
The goal is not to shame someone for mouth breathing. The goal is to find out why nasal breathing is difficult and address the cause when treatment is appropriate.
How is mouth breathing diagnosed?
A healthcare provider starts with a physical examination and looks inside the nose and throat. The clinician may ask when mouth breathing occurs, whether it happens during sleep, and whether symptoms include congestion, snoring, drooling or tiredness.
Simple office checks may help assess whether a person can breathe through the nose.
Check | What it evaluates |
Lip-seal test | Whether the person can breathe comfortably with the mouth closed. |
Mirror test | Whether a mirror held under the nose develops clouding or condensation, suggesting nasal breathing. |
Water test | Whether the person can hold water in the mouth, which requires breathing through the nose. |
The evaluation may also consider possible causes such as allergies, infection, a deviated septum, swollen turbinates, enlarged adenoids or tonsils, nasal polyps and sleep apnea.
How is mouth breathing treated?
Treatment addresses the condition that makes nasal breathing difficult. The appropriate option depends on the cause, the person’s age, the duration of symptoms and other health factors.
Treatment approach | When it may be considered |
Allergy medication | Antihistamines or steroid nasal sprays may ease allergy symptoms. |
Cold-related treatment | Antihistamines or decongestants may help when a cold causes a stuffy nose. |
Treatment for persistent sinus infection | Antibiotics may be prescribed for a sinus infection lasting more than 10 days. |
Adenoidectomy | Surgery to remove infected or swollen adenoids that block a child’s airway. |
Septoplasty | Surgery to correct a deviated septum and improve nasal airflow. |
Turbinate reduction | Surgery to reduce turbinate size so air can move through the nose. |
Medication and surgery decisions should be made with a healthcare provider. Do not use prescription nasal sprays, antibiotics, decongestants or other treatments without appropriate guidance.
Medication for allergies
Antihistamines or steroid nasal sprays may be recommended to ease allergy symptoms that contribute to congestion. A provider can explain which option is appropriate and how it should be used.
Medication for a cold
When a cold causes a stuffy nose, antihistamines or decongestants may help. A clinician or pharmacist can advise on safe use, especially for children or people taking other medicines.
Treatment for sinus infection
Antibiotics may be used for a sinus infection that lasts more than 10 days. Antibiotics are not appropriate for every cause of congestion, so they should be prescribed by a healthcare professional.
Adenoidectomy
An adenoidectomy removes infected or swollen adenoids that block a child’s airway. A clinician can discuss whether enlarged adenoids are contributing to mouth breathing and whether surgery is appropriate.
Septoplasty
Septoplasty corrects a deviated septum so it is easier for air to move through the nose. A specialist can explain the potential benefits and risks for the individual.
Turbinate reduction
Turbinate reduction reduces the size of swollen turbinates so air can pass through the nose. It may be considered when turbinate enlargement contributes to persistent nasal obstruction.
Can mouth breathing be prevented?
Some causes of mouth breathing cannot be prevented, but early attention to congestion and sleep symptoms may help reduce the chance that mouth breathing becomes a persistent habit in a child.
Prevention habit | What to watch for |
Notice chronic stuffiness | Ongoing nasal congestion can make nasal breathing difficult and increase the chance of habitual mouth breathing. |
Address congestion | Ask a healthcare provider how to manage recurring or persistent congestion. |
Check sleeping habits | Snoring or restless sleep may signal difficulty breathing through the nose. |
Observe daytime breathing | Notice whether a child or adult breathes through the mouth more often than the nose. |
Seek evaluation early | Persistent symptoms are easier to understand when a provider examines the nose and airway. |
Do not tape a person’s mouth shut or force a child to breathe through the nose. If nasal breathing is difficult, the underlying reason should be evaluated first.
Mouth breathing at night: what should I look for?
Nighttime clues include drooling on the pillow, dry mouth on waking, bad breath, snoring and restless sleep. A person may also feel tired during the day because sleep is not restorative.
For a child, ask whether they often sleep with the mouth open, snore, toss and turn, wake with a dry mouth or show daytime irritability and restlessness. These signs do not confirm sleep apnea, but they are useful information to share with a pediatrician.
Adults who think they mouth-breathe during sleep should also talk with a healthcare provider, particularly if snoring and daytime tiredness occur together.
When should I see a healthcare provider?
Talk to a healthcare provider if you notice persistent mouth breathing, bad breath, drooling on the pillow, dry mouth, hoarseness, snoring or ongoing tiredness.
Ask a child’s pediatrician to assess the nose and airway if the child often breathes through the mouth or has related symptoms. Persistent mouth breathing in children deserves attention because sleep, behavior, growth and facial development may be affected.
Seek prompt medical care for severe breathing difficulty, blue or gray lips, choking, or another immediate breathing emergency. These symptoms require urgent attention regardless of the cause.
What questions should you ask at a mouth breathing visit?
Useful questions at a mouth breathing visit cover what is blocking nasal breathing, whether allergies, adenoids or sleep apnea play a role, and which treatments may help.
What could be making nasal breathing difficult?
Is congestion, allergy, infection, anatomy or sleep apnea contributing?
Should the nose and throat be examined by a specialist?
Could enlarged adenoids or tonsils be blocking the airway?
Would an allergy medicine or nasal spray be appropriate?
How should a cold-related stuffy nose be treated?
Could a deviated septum or enlarged turbinates be contributing?
Should sleep symptoms be evaluated further?
What signs should prompt urgent care?
If surgery is suggested, what problem would it address?
Conclusion: Find the reason nasal breathing is difficult
Mouth breathing is frequent breathing through the mouth instead of the nose. It may occur because congestion, allergies, a deviated septum, swollen turbinates, enlarged adenoids or tonsils, nasal polyps or sleep apnea makes nasal airflow difficult.
Dry mouth, bad breath, nighttime drooling, snoring, hoarseness and tiredness are common clues. In children, persistent mouth breathing may affect sleep, behavior, growth and facial shape.
A healthcare provider can examine the nose and throat, perform simple airflow checks and identify the cause. Treatment focuses on that underlying problem and may include medication or surgery. If mouth breathing persists or occurs during sleep, schedule an evaluation rather than trying to force nasal breathing without understanding the blockage.
Frequently Asked Questions
What is mouth breathing?
Mouth breathing is frequently taking air through the mouth instead of the nose. It may happen when nasal airflow is restricted by congestion, swelling, anatomy, growths or sleep apnea.
Is mouth breathing normal?
Brief mouth breathing during exercise or intense activity can be normal. Persistent mouth breathing, especially when it is the main way a person breathes or occurs during sleep, should be discussed with a healthcare provider.
What are the most common mouth breathing symptoms?
Common symptoms include dry mouth, bad breath, drooling during sleep, tiredness, hoarseness and snoring.
Why does my child breathe through their mouth?
A child may mouth-breathe because nasal airflow is limited by congestion, allergies, enlarged adenoids or tonsils, swollen turbinates, nasal polyps or another airway or sleep problem.
Can mouth breathing change a child’s face?
Persistent mouth breathing may contribute to a narrow facial shape, a receding chin or jaw, or upper and lower teeth that do not line up. A pediatrician should assess the child’s nose and airway.
Does mouth breathing cause ADHD?
Mouth breathing does not establish ADHD. Some children who mouth-breathe may also have sleep apnea or another sleep issue, and poor sleep can contribute to irritability, restlessness and behavior patterns similar to those seen in ADHD.
Can mouth breathing affect growth?
Mouth breathing is not directly responsible for growth issues. However, an airway blockage that leads a child to mouth-breathe may affect growth-related hormone release. A pediatrician should assess any growth concern.
How is mouth breathing diagnosed?
A provider examines the nose and throat and may use a lip-seal test, mirror test or water test. The evaluation also considers possible causes such as congestion, allergies, anatomy, enlarged tissue, nasal polyps and sleep apnea.
How is mouth breathing treated?
Treatment addresses the cause of restricted nasal airflow. Options may include antihistamines, steroid nasal sprays, medicines for cold-related congestion, antibiotics for a sinus infection lasting more than 10 days, adenoidectomy, septoplasty or turbinate reduction.
Should I tape my mouth shut at night?
No. If nasal breathing is difficult, forcing the mouth closed can be unsafe. Persistent mouth breathing should be evaluated so the underlying cause can be addressed.
When should I see a doctor for mouth breathing?
Talk to a healthcare provider for persistent mouth breathing, dry mouth, bad breath, nighttime drooling, snoring or tiredness. Ask a child’s pediatrician to evaluate a child who often mouth-breathes or has related sleep or behavior symptoms.
Is mouth breathing dangerous for adults?
Mouth breathing in adults is generally not a serious health issue by itself, but persistent symptoms may reflect nasal blockage or a sleep-related breathing problem that deserves evaluation.
Related guides
Related guides for mouth breathing cover nasal congestion, nasal polyps, adenoids, allergic rhinitis and dry mouth.
Related Reading
Obstructive Sleep Apnea: Symptoms, Causes, and What Actually Helps explains how blocked airways during sleep cause snoring and breathing pauses.
Adenoids: Function, Location, and Health Impact explains how enlarged adenoids can block the nose and cause mouth breathing.
Nasal Congestion: Causes, Symptoms, and Effective Relief Strategies explains why the nose gets stuffy and how to clear it.
Dry Mouth: Symptoms, Causes, Diagnosis and Treatment — What You Need to Know explains dry mouth causes and how to protect teeth and gums.
References
National Heart, Lung, and Blood Institute (NHLBI). What Is Sleep Apnea? National Institutes of Health. Last updated January 9, 2025. https://www.nhlbi.nih.gov/health/sleep-apnea
Bakker JP, Zhang F, Amin R, et al. Adenotonsillectomy and health care utilization in children with snoring and mild sleep apnea: a randomized clinical trial. JAMA Pediatr. 2025;179(6):600-609. PMID 40094698. https://doi.org/10.1001/jamapediatrics.2025.0023
Yu PK, Cook K, Tapia IE, et al. Symptoms, quality of life, and executive function in children who snore. JAMA Otolaryngol Head Neck Surg. 2025;151(2):151-159. PMID 39699925. https://doi.org/10.1001/jamaoto.2024.4373
Disclaimer
This article is for general educational purposes and is not a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified healthcare professional with any questions about a medical condition or treatment.
Do not tape a person’s mouth shut or force nasal breathing when airflow may be blocked, and do not use prescription nasal sprays, antibiotics or decongestants without guidance. Seek urgent medical help for severe breathing difficulty, blue or gray lips or choking.
Comments