Post-Nasal Drip: Causes, Treatment and When It Means Sinusitis
Why it's worse at night, what actually causes it, and how to work out which treatment will help.
Part of our Sinusitis condition guide.
The headline: You produce around a litre of nasal mucus a day and swallow nearly all of it without noticing. Post-nasal drip is rarely about making more mucus—it's usually about mucus becoming thicker, or the throat becoming more sensitive to what was always there.
Sinus Symptoms Assessed Online
Where post-nasal drip comes with facial pressure, nasal blockage and reduced smell, Access Doctor's GPhC-registered pharmacist independent prescribers can assess you online and recommend treatment.
View Sinusitis Treatments →What post-nasal drip actually is
The lining of your nose and sinuses produces mucus continuously—roughly a litre a day. It traps dust, bacteria and irritants, and tiny hairs called cilia sweep it steadily backwards to be swallowed. This happens every minute of every day and you never notice it.
Post-nasal drip is what happens when you start noticing. That occurs when one of three things changes:
The mucus thickens
Thicker mucus moves more slowly and is felt as it passes, rather than being cleared silently.
There is more of it
Inflammation from infection or allergy increases production well beyond the usual volume.
The throat is more sensitive
An irritated throat lining registers a normal amount of mucus as an abnormal sensation.
The third point explains something patients are often told unhelpfully. If you've been examined and told everything looks normal, that doesn't mean the sensation is imagined—it means the problem is sensitivity rather than volume.
What it feels like
- A sensation of mucus trickling down the back of the throat
- Needing to clear your throat frequently, often without thinking about it
- A cough that's worse lying down and on waking
- A raw or scratchy throat, typically worse first thing
- Occasional hoarseness, particularly in the morning
- A feeling of something stuck in the throat that swallowing doesn't shift
- Bad breath
- Nausea in the morning from swallowed mucus overnight
Why it's worse at night
Almost everyone with post-nasal drip describes it as worse at night and on waking. There are three reasons, and each suggests something you can change.
1
Gravity stops helping
Upright, mucus drains forwards and downwards. Lying flat, it pools at the back of the throat instead. Raising the head of the bed by 10–15cm restores some of that drainage.
2
You stop swallowing
Awake you swallow every minute or so without noticing. Asleep, swallowing becomes infrequent, so mucus accumulates until it triggers a cough.
3
Bedroom air is dry
Central heating drops humidity sharply. Dry air thickens mucus and dries the throat lining, making both more irritating. A humidifier or a bowl of water near the radiator helps.
The five main causes
| Cause | Typical pattern | Clues |
|---|---|---|
| Sinusitis | Thick mucus, often discoloured | Facial pressure, blocked nose, reduced smell |
| Allergic rhinitis | Clear, watery, plentiful | Sneezing, itchy eyes and nose, seasonal or trigger-linked |
| Non-allergic rhinitis | Clear, variable | Triggered by cold air, strong smells, alcohol, spicy food. Allergy tests negative |
| Acid reflux | Often no visible mucus at all | Worse after meals and lying down, throat clearing, hoarseness, sometimes heartburn |
| Viral infection | Follows a cold | Settles within a few weeks. The commonest cause overall |
Less common contributors include a deviated septum, nasal polyps, pregnancy, some blood pressure medicines, and overuse of decongestant nasal sprays—which causes rebound congestion after more than a week of use.
Working out which one you have
| Ask yourself | What the answer suggests |
|---|---|
| Is there facial pressure over the cheeks or forehead? | Yes points to sinusitis |
| Is your sense of smell reduced? | Yes points to sinusitis or polyps |
| Are your eyes itchy and are you sneezing? | Yes points to allergy |
| Is it clearly seasonal, or tied to pets or dust? | Yes points to allergy |
| Is it worse after meals or when you lie down soon after eating? | Yes points to reflux |
| Is it triggered by cold air, perfume, alcohol or spicy food? | Yes points to non-allergic rhinitis |
| Did it start with a cold and is it slowly improving? | Post-viral, and likely to settle |
| Is the mucus thick and discoloured rather than clear and watery? | Points towards sinusitis rather than allergy |
More than one cause is common. Allergy narrows the sinus drainage channels, which predisposes to sinusitis, which then produces its own post-nasal drip. Treating only one may only partly help.
When it means sinusitis
Post-nasal drip is a recognised feature of sinusitis, and often the last symptom to go once everything else has settled.
What makes sinusitis the likely explanation is the combination:
- Facial pain or pressure over the cheeks, forehead or between the eyes, worse bending forward
- A blocked nose that doesn't clear
- Reduced or absent sense of smell
- Thick, often discoloured mucus rather than clear and watery
- A recent cold that never fully resolved
If that's your picture and it's passed the 10-day mark without improvement, it's worth being assessed. Our guides on bacterial or viral sinusitis and whether antibiotics are needed explain what happens next.
Post-nasal drip lasting beyond 12 weeks with facial pressure and blockage points towards chronic sinusitis, which is managed differently and often needs a longer course of a steroid nasal spray.
Post-nasal drip and chronic cough
Post-nasal drip is one of the three leading causes of a chronic cough in adults, alongside asthma and reflux. Mucus dripping onto the larynx triggers the cough reflex directly.
The characteristic pattern is a dry or barely productive cough, worse on lying down and on waking, accompanied by throat clearing and often a slightly hoarse morning voice.
A cough lasting more than three weeks should be assessed rather than assumed. Don't attribute a persistent cough to post-nasal drip without a proper look at the alternatives, particularly if you smoke, have ever smoked, or are coughing anything blood-stained.
The throat-clearing cycle
This is worth its own section because it's both common and fixable.
Forceful throat clearing slams the vocal cords together. That traumatises the lining, which responds by producing more mucus and becoming more irritated—which makes you want to clear your throat again. The habit sustains the symptom.
Instead of clearing your throat:
- Swallow firmly—often as effective and far gentler
- Take a sip of water
- Use a small silent cough rather than the harsh scraping sound
- Hum for a few seconds, which moves the vocal cords without impact
Expect it to take a couple of weeks. It's a habit, and it improves as habits do—gradually, with attention.
Self-care that works
- Saline nasal rinsing—the single most useful measure, and it helps regardless of cause. Once or twice daily with a purpose-made kit and cooled boiled or distilled water.
- Fluids—well-hydrated mucus is thinner and clears more easily.
- Raise the head of the bed—10 to 15cm under the bed legs, not extra pillows, which bend the neck.
- Humidify the bedroom—particularly through the heating season.
- Avoid known triggers—smoke, strong perfumes, very dry air.
- Limit alcohol in the evening—it worsens both reflux and nasal congestion.
- Don't eat within three hours of bed if reflux is a possibility.
Treatment by cause
| Cause | What helps |
|---|---|
| Post-viral | Saline rinsing, fluids, time. Usually settles within a few weeks. |
| Acute sinusitis, under 10 days | Saline rinsing, steam, pain relief, head elevated. |
| Sinusitis past 10 days | A steroid nasal spray to reduce inflammation. Antibiotics only where bacterial infection is likely. |
| Chronic sinusitis | Longer-term steroid nasal spray plus regular saline rinsing. GP or ENT review. |
| Allergic rhinitis | Antihistamines, allergen avoidance, a steroid nasal spray. See our allergy guides. |
| Non-allergic rhinitis | Trigger avoidance, saline rinsing. Some people need a prescribed spray. |
| Reflux | Meal timing, raising the bed head, weight and alcohol where relevant, and reflux treatment if needed. |
Where post-nasal drip is part of sinusitis that's passed the 10-day mark, Access Doctor supplies mometasone nasal spray for sinusitis and beclometasone nasal spray for sinusitis. Where a bacterial infection is genuinely likely, phenoxymethylpenicillin or, for those who can't take penicillin, doxycycline may be appropriate. All are prescription-only and follow an online consultation reviewed by a pharmacist independent prescriber. Our comparison of steroid spray versus antibiotics covers which is likely to help.
When to see a doctor
Arrange an appointment if post-nasal drip has lasted more than a few weeks without explanation, if it comes with facial pain and reduced smell, if a cough is disturbing your sleep, or if self-care hasn't helped.
Seek prompt medical advice for: one-sided nasal blockage or discharge; blood-stained mucus; difficulty or pain on swallowing; hoarseness lasting more than three weeks; a lump in the neck; unexplained weight loss; or numbness in the face. These are uncommon but need proper assessment rather than self-management.
Treat the Sinusitis Behind the Drip
If post-nasal drip comes with facial pressure, a blocked nose and reduced smell past day 10, treating the sinus inflammation is what resolves it. Complete a short online consultation reviewed by a GPhC-registered pharmacist independent prescriber.
Start Sinusitis Consultation →Frequently Asked Questions
What is post-nasal drip?
Post-nasal drip is the sensation of mucus running down the back of the throat from the nose and sinuses. Your body produces roughly a litre of nasal mucus every day and normally you swallow it without noticing. You become aware of it when the mucus changes, becoming thicker or more copious, or when the throat becomes more sensitive to it. The sensation is real even when nothing abnormal can be seen.
Why is post-nasal drip worse at night?
Three things change when you lie down. Gravity no longer helps mucus drain forwards, so it pools at the back of the throat. You swallow far less often while asleep, so it accumulates rather than clearing. And bedroom air is often dry, particularly with central heating, which thickens mucus and makes it more irritating. Together these explain why many people cough on lying down and again on waking.
Is post-nasal drip a sign of sinusitis?
It can be, but it is not specific. Post-nasal drip is one of the recognised features of sinusitis, and it is often the symptom that lingers longest afterwards. What points towards sinusitis is the company it keeps: facial pain or pressure over the cheeks or forehead, a blocked nose and a reduced sense of smell. Post-nasal drip without any of those is more likely to be allergy, reflux or non-allergic rhinitis.
How do I get rid of post-nasal drip?
Treatment depends on the cause, which is why untargeted remedies often disappoint. Saline nasal rinsing helps almost every cause and is the sensible starting point. Beyond that, allergy responds to antihistamines and steroid sprays, sinusitis to treatment of the sinus inflammation, reflux to reflux measures, and non-allergic rhinitis to avoiding triggers. Raising the head of the bed and keeping well hydrated help regardless of cause.
Can post-nasal drip cause a sore throat?
Yes. Mucus running over the throat lining irritates it, and the constant throat clearing that people do in response causes further irritation. The result is a throat that feels raw or scratchy, often worse first thing in the morning and easing during the day. Unlike an infective sore throat, it does not usually come with fever or swollen glands, and it persists for weeks rather than resolving in a few days.
Can post-nasal drip cause a persistent cough?
It is one of the most common causes of a chronic cough, alongside asthma and reflux. Mucus dripping onto the voice box and upper airway triggers the cough reflex. The pattern is typically a dry or minimally productive cough that is worse on lying down and on waking, often with throat clearing. A cough lasting more than three weeks should be assessed rather than assumed to be post-nasal drip.
Does clearing your throat make post-nasal drip worse?
Yes, and this is one of the more useful things to know. Forceful throat clearing traumatises the throat lining, which produces more mucus and more irritation, prompting more throat clearing. Breaking that cycle helps. Try a firm swallow, a sip of water or a gentle cough instead of the harsh clearing sound, and expect the habit to take a couple of weeks to unlearn.
When should I see a doctor about post-nasal drip?
Arrange assessment if it has lasted more than a few weeks without explanation, if it comes with facial pain, a blocked nose and reduced smell suggesting sinusitis, or if self-care has not helped. Seek prompt medical advice for one-sided nasal blockage or discharge, blood-stained mucus, difficulty swallowing, a hoarse voice lasting more than three weeks, a lump in the neck or unexplained weight loss.
Completing the treatment
Post-nasal drip caused by sinusitis resolves when the sinus inflammation does. Access Doctor supplies steroid nasal sprays and, where genuinely indicated, antibiotics for adults, following a short online consultation reviewed by a GPhC-registered pharmacist independent prescriber. See the options on the sinusitis treatment page.
Steroid spray · Rx
Mometasone Nasal Spray for Sinusitis
Reduces the inflammation driving persistent drip.
View product →Steroid spray · Rx
Beclometasone Nasal Spray for Sinusitis
Alternative steroid nasal spray, taken twice daily.
View product →Antibiotic · Rx
Phenoxymethylpenicillin for Sinusitis
Where a bacterial sinus infection is genuinely likely.
View product →Antibiotic · Rx
Doxycycline Capsules for Sinusitis
Alternative where penicillin cannot be used.
View product →References
- NHS. Post-nasal drip. nhs.uk
- NHS. Sinusitis (sinus infection). nhs.uk
- NICE Clinical Knowledge Summaries. Cough. cks.nice.org.uk
- NICE Clinical Knowledge Summaries. Sinusitis. cks.nice.org.uk
- NICE Clinical Knowledge Summaries. Allergic rhinitis. cks.nice.org.uk
- National Institute for Health and Care Excellence. Sinusitis (acute): antimicrobial prescribing (NG79). nice.org.uk
- NHS. Heartburn and acid reflux. nhs.uk
Medical disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional for diagnosis and treatment. In a medical emergency, call 999.