Postnasal Drip: Detailed Guide

Author: Op. Dr. Javidan Asafov · ENT / Otolaryngology Specialist · Last medical review: 21.10.2026

Why does the nose produce mucus?

The inside of the nose and the sinuses are covered with a thin lining called the mucosa. Glands in this lining produce a sticky secretion (mucus) that moistens the air you breathe and traps dust, pollen and germs. Tiny hairs on the surface of the lining constantly carry this mucus towards the back of the nose and from there down into the throat. The mucus is swallowed without being noticed and is made harmless by stomach acid.

This cleaning system works day and night. A healthy nose produces a considerable amount of mucus every day; however, because the mucus is runny and is moved along steadily, it is not felt. When the mucus increases, thickens or is moved along more slowly, it builds up in the throat and is noticed as postnasal drip. This is why postnasal drip is most often a sign that the nose and sinuses are reacting to something.

Discharge or sensation?

Not everyone who complains of postnasal drip actually has more mucus. In some people the amount of mucus is normal, but because the throat has become more sensitive, even a normal amount of mucus becomes noticeable. A recent infection, reflux, dry air or cigarette smoke can increase this sensitivity by stimulating the nerve endings in the throat.

A common vicious circle arises here: the feeling that “there is something in my throat” leads to frequent throat clearing; constant throat clearing and coughing irritate the throat and larynx; and an irritated throat feels as if there is even more mucus. Recognising this circle is an important part of treatment. When the urge to clear your throat comes, swallowing or taking a sip of water instead can gradually reduce the habit.

In people who have a constant feeling of phlegm in the throat but no obvious discharge in the nose and the back of the nose on examination, reflux, throat sensitivity and the throat-clearing habit are assessed together.

Causes

The causes of postnasal drip fall into a few main groups. More than one cause may be present in the same person; for example, allergic rhinitis may be accompanied by a deviated septum or reflux.

Allergic rhinitis

A nasal allergy to pollen, house dust mites, animal dander or mould is one of the most common causes of postnasal drip. The discharge is usually clear and watery; sneezing, an itchy nose, blockage and itchy eyes may accompany it. In year-round allergy, sneezing may fade into the background, and postnasal drip and blockage may be the only symptoms (allergic rhinitis).

Non-allergic rhinitis

In people whose nose runs often although their allergy tests are negative, the nasal lining may be oversensitive to certain triggers. Cold or dry air, sudden changes in temperature, strong smells, perfume, cigarette smoke and air pollution can set off the discharge. In some people the nose runs when eating hot or spicy food. This type of rhinitis is more common in older age; with age, nasal secretions can also become more watery and more noticeable.

Infections and sinusitis

During a cold or flu the discharge increases and may continue for a while after recovery; this usually clears up on its own. In acute sinusitis, thick, yellow-green discharge comes with nasal blockage and a feeling of fullness and pressure in the face. In chronic sinusitis the symptoms are less marked but constant; thick postnasal drip, blockage and a reduced sense of smell are the main features. Nasal polyps may also be part of this picture (sinusitis).

Structural causes in the nose

A bend in the septum, the central wall of the nose (deviated septum), and enlarged turbinates (turbinate hypertrophy) disturb airflow, make it harder for mucus to be moved along steadily and can affect ventilation of the sinuses. Breathing through the mouth because of blockage also dries the throat, so the mucus feels thicker.

Medicines and environmental factors

Some blood pressure medicines and medicines containing hormones can cause blockage and discharge by making the nasal lining swell. Decongestant nasal sprays, which should be used only for short-term relief, also make the lining swell and increase blockage when used for a long time (nasal spray addiction). If you think a medicine you are taking may be related to your symptoms, do not stop it on your own; talk to your doctor about it. Centrally heated or air-conditioned rooms, not drinking enough fluids and smoking all contribute to the mucus becoming thicker.

Pregnancy and hormonal changes

During pregnancy, hormonal changes can make the nasal lining swell; blockage and postnasal drip are common and usually clear up on their own after the birth. During this time, do not use any medicine, including over-the-counter nasal sprays, without consulting your doctor.

The link with reflux

The backflow of stomach contents into the oesophagus is called reflux. In some people, reflux passes the upper end of the oesophagus and reaches the throat and larynx; this is called laryngopharyngeal reflux. Because this type of reflux often causes no heartburn, it is also known as “silent reflux”.

Reflux itself is not a nasal discharge. However, irritation of the larynx and throat leads to a build-up of protective mucus there and a feeling that there is phlegm in the throat. People often describe this as postnasal drip. Constant throat clearing, a feeling of a lump or something stuck in the throat, marked hoarseness in the morning, a sour or bitter taste in the mouth and a dry cough may suggest reflux. Reflux can also contribute to bad breath.

On endoscopic examination, redness and swelling caused by reflux may be seen in the larynx; however, because these findings can also have other causes, they are not enough on their own for a diagnosis. The assessment is made by considering the symptoms and the examination findings together. When reflux is suspected, changes to diet and lifestyle come first: eating an early, light evening meal; not lying down straight after eating; keeping the head slightly raised in bed; losing excess weight; cutting down on foods and drinks that you notice make your symptoms worse, such as coffee, tea, fizzy drinks, chocolate, alcohol and fatty foods; and stopping smoking. If needed, medicines that reduce stomach acid may be used on the doctor’s advice. Because postnasal drip and reflux can occur together, both often need to be addressed at the same time.

Postnasal drip in children

In children, the most common causes of postnasal drip are frequent upper respiratory tract infections, allergic rhinitis and enlarged adenoids. The adenoids are lymphoid tissue at the back of the nose; when they are enlarged, they narrow the back of the nose, disturb the flow of mucus and can themselves become inflamed and a source of discharge. A constantly runny nose, sleeping with the mouth open, snoring, coughing at night and in the morning, and frequently recurring ear infections suggest enlarged adenoids (adenoids and tonsils in children).

In children, sinusitis can also cause thick postnasal drip and a cough that gets worse especially when lying down. In young children, foul-smelling discharge coming from only one side of the nose suggests a foreign body in the nose; in this case, do not put off an examination. In children, rinsing the nose with saline and keeping the nose clean regularly are the basic measures; medicines are chosen from those suitable for the child’s age, on the doctor’s advice.

Examination and tests

Assessment starts with a detailed history. You will be asked how long the discharge has been going on, what colour and consistency it is and whether it changes during the day or with the seasons, and about nasal blockage, sneezing, a reduced sense of smell, fullness in the face, heartburn, a sour taste in the mouth, cough, voice changes, smoking, your work environment and the medicines you use.

The inside of the nose, the back of the nose and the larynx are then examined endoscopically with a thin camera. This examination is quick and usually well tolerated. It allows assessment of infected discharge coming from the sinus openings, pale and swollen lining due to allergy, polyps, a deviated septum, enlarged turbinates, adenoids in children and signs of reflux-related irritation in the larynx.

Not everyone needs tests; they are chosen according to the examination findings. If allergy is suspected, skin tests or blood tests measuring allergy-specific antibodies may be requested. If chronic sinusitis or polyps are suspected, especially if symptoms persist despite medical treatment, a CT scan of the sinuses may be carried out. If cough is the main symptom and the nasal findings do not explain the symptoms, a chest X-ray or breathing tests may also be requested if needed.

Treatment steps

Treatment of postnasal drip is aimed at the underlying cause; your doctor decides which medicine to use and how. At every step, staying away from irritants, drinking enough fluids and rinsing the nose with saline are part of the treatment.

• Rinsing the nose with saline: it clears away thick mucus, allergens and irritants, makes it easier for mucus to be moved along and helps nasal sprays work better. A ready-made solution, or a solution prepared with boiled and cooled or sterile water, should be used.
• Intranasal corticosteroid sprays: in allergic rhinitis and chronic sinusitis, they reduce swelling of the lining and secretions. Their effect builds up with regular use; using them only when you have symptoms does not give the expected relief.
• Antihistamines: they can be used as tablets or nasal sprays for discharge, sneezing and itching caused by allergy.
• Allergen avoidance: measures that reduce contact with house dust mites, pollen, pets and mould can ease symptoms.
• In non-allergic rhinitis: avoiding triggers is the basic measure; if watery discharge is the main problem, sprays that reduce nasal secretions are also among the options.
• Treatment of sinusitis: if sinusitis is present, treatment is adjusted accordingly; if bacterial sinusitis is suspected, antibiotics may be given on the doctor’s advice.
• If reflux is present: changes are made to diet and lifestyle; if needed, medicines that reduce stomach acid are added on the doctor’s advice.

Decongestant nasal sprays can be used only for short-term relief; long-term use leads to medication-induced congestion. If symptoms persist despite treatment, whether the medicines are being used correctly is checked, the diagnosis is reconsidered and other possible accompanying causes are looked into.

The role of surgery

There is no operation for postnasal drip itself; surgery aims to correct a structural or chronic problem that is causing the discharge and has not responded to medical treatment. In suitable patients, the following options may be considered:

• Endoscopic sinus surgery: in chronic sinusitis and nasal polyps that persist despite medical treatment, the sinus openings are widened to restore ventilation and the drainage of mucus (sinusitis).
• Septoplasty: a bend in the central wall of the nose that markedly narrows the airway is straightened (deviated septum).
• Turbinate reduction: the volume of enlarged turbinates is reduced while preserving their function (turbinate hypertrophy).
• Adenoid surgery (adenoidectomy): in children, enlarged adenoids that are causing symptoms are removed (adenoids and tonsils in children).

Causes such as allergic rhinitis or reflux are not removed by surgery; if they are present, their treatment continues after surgery too. The decision to operate is made together with the person, based on the examination and, if needed, CT findings.

Chronic cough and postnasal drip

Postnasal drip is one of the most common causes of a long-lasting cough. In medical terms, this cough arising from the nose and sinuses is also called upper airway cough syndrome. Mucus running down into the throat and irritation in the throat stimulate the cough reflex; the cough gets worse especially when lying down at night and on getting up in the morning. Throat clearing and a tickly throat often accompany it.

The other common causes of a long-lasting cough are asthma and reflux; these causes may occur together. Some blood pressure medicines can also cause a dry cough. In people with nasal and sinus findings, treatment is planned starting with the nose; if the cough eases as the nasal symptoms improve, this confirms the cause. Do not put off an examination if the cough comes with shortness of breath, wheezing, blood in the phlegm, fever or unexplained weight loss.

Frequently asked questions

Why won’t my postnasal drip go away? It most often continues because an underlying cause, such as allergic rhinitis, chronic sinusitis, reflux or nasal blockage, is still present. Sometimes more than one cause plays a part, or a constant throat-clearing habit keeps the symptom going. Identifying the cause through examination and following regular treatment aimed at it brings noticeable relief in most people.

Does yellow or green discharge mean a bacterial infection? Not always. The colour of the discharge comes from inflammatory cells and can also be seen in viral infections such as a cold. Whether antibiotics are needed is decided not by the colour of the discharge but by how the symptoms progress and by the examination findings.

Do milk and dairy products increase phlegm? Research has not shown that dairy products increase nasal and sinus secretions. Some people may describe a coated feeling in the mouth and throat after drinking milk; however, this does not mean that secretions have increased. There is no need to cut out dairy products unless you notice a clear link.

Is it harmful to swallow the phlegm running down into the throat? No. Swallowing nasal mucus is normal and happens every day in healthy people too; swallowed mucus is made harmless by stomach acid. Trying to force phlegm out, on the other hand, can irritate the throat more.

Can I rinse my nose with saline regularly? Yes. Rinsing the nose with saline is generally safe and can be done regularly. It is important to use a ready-made solution, or to prepare the solution with boiled and cooled or sterile water, and to keep the rinsing bottle clean. If you notice a feeling of fullness or burning in the ear, go over your rinsing technique with your doctor.

Will surgery cure postnasal drip? If the cause of the discharge is chronic sinusitis, polyps, a markedly deviated septum, enlarged turbinates or, in children, enlarged adenoids, and medical treatment has not been enough, surgery can noticeably reduce the discharge by correcting that cause. Causes such as allergy or reflux are not cured by surgery; this is why the decision to operate is based on the examination findings.

This article is for general information; please consult your physician for diagnosis and treatment.