Why do people drool when they are sick?

September 26, 2025 •

3 min read

While typically a harmless and temporary symptom, excessive drooling—known as sialorrhea—is a common and often overlooked side effect of illness. Understanding why do people drool when they are sick sheds light on the body's natural defense mechanisms and responses to infection.

Quick Summary

Drooling when ill is often due to a combination of factors, including the body's increased saliva production to combat irritation from infections or acid reflux, difficulty swallowing caused by a sore throat or tonsillitis, and the relaxation of facial muscles during sleep. Nausea can also trigger a protective reflex that increases salivation to shield the esophagus from stomach acid.

Key Points

Hypersalivation: Your body increases saliva production as a defense mechanism to flush out bacteria or neutralize acid from reflux.
Infections Cause Drooling: Throat and sinus infections can cause pain or swelling that makes swallowing difficult, leading to a buildup of saliva.
Nausea Trigger: The feeling of nausea triggers a protective reflex to produce more saliva, which neutralizes stomach acid and protects the esophagus.
Sleep Position: Sleeping on your side or back with an elevated head can help manage saliva flow, especially when nasal congestion causes mouth breathing.
Swallowing Difficulty: A severe sore throat or swollen tonsils can inhibit swallowing, causing saliva to pool and drool.
Congestion Factor: Blocked nasal passages force mouth breathing, leading to more saliva accumulating and leaking out, particularly during sleep.

The Body’s Defensive Saliva Production

Excessive saliva production, known medically as hypersalivation, is a natural and often beneficial response by the body to protect itself when you are sick. During an infection, the body may increase saliva flow to help clear bacteria and viruses from the mouth and throat, preventing them from spreading further.

Infections that Cause Increased Saliva

Throat and Mouth Infections: Conditions like strep throat, tonsillitis, and mononucleosis cause inflammation and irritation in the mouth and throat. In response, your salivary glands may produce more saliva to keep tissues moist and help flush away bacteria, pus, or other irritants.
Sinus Infections: Nasal congestion from a sinus infection often leads to mouth breathing, which can cause saliva to pool and eventually spill out of the mouth. Additionally, post-nasal drip from excess mucus can irritate the back of the throat and trigger an increase in saliva production.
Oral Thrush: This fungal infection can cause a sore, irritated mouth, prompting the body to create more saliva to soothe the affected areas.

Gastrointestinal Issues and Drooling

Drooling and excessive salivation are also common with digestive issues, especially those involving nausea and acid reflux.

Nausea: When you feel nauseous, your brain sends signals to your salivary glands to produce more saliva. This is a protective reflex intended to neutralize stomach acid in case you vomit, shielding your teeth and esophagus from damage. The pooling of this extra saliva, combined with feeling too unwell to swallow frequently, can lead to drooling.
Gastroesophageal Reflux Disease (GERD): Acid reflux causes stomach contents to flow back into the esophagus. The body's response is to produce more saliva to wash the acid away and protect the esophageal lining from irritation.

Neurological and Muscular Factors

Sometimes, the issue isn't producing too much saliva, but rather an impaired ability to manage normal saliva flow. Illness can affect the muscles and neurological pathways responsible for swallowing.

Difficulty Swallowing (Dysphagia): A severe sore throat or swollen tonsils can make swallowing painful and difficult. When swallowing is reduced, saliva pools in the mouth and escapes, causing drooling.
Muscle Relaxation During Sleep: Many people breathe through their mouths when they are sick due to nasal congestion. When sleeping, the muscles of the mouth and jaw relax, making it easier for pooled saliva to dribble out.

Comparison: Drooling Causes When Sick


Cause	Mechanism	Associated Symptoms
Throat Infection	Inflamed throat makes swallowing painful and difficult.	Sore throat, fever, swollen lymph nodes.
Sinus Infection	Blocked nasal passages lead to mouth breathing and post-nasal drip.	Congestion, headache, mucus buildup.
Nausea	Protective reflex increases saliva to neutralize stomach acid before vomiting.	Upset stomach, urge to vomit, loss of appetite.
Acid Reflux	Stomach acid irritates the esophagus, triggering more saliva to neutralize it.	Heartburn, sour taste in mouth, throat clearing.

How to Manage Drooling When Sick

While drooling during sickness is often temporary and resolves with the underlying illness, there are a few strategies to manage the symptom:

Stay Hydrated: Frequent, small sips of water can help manage saliva buildup and encourage swallowing.
Adjust Your Sleeping Position: Sleeping on your back with your head slightly elevated can help control drooling by using gravity to keep saliva in your mouth.
Treat Nasal Congestion: Use saline nasal sprays or a humidifier to clear blocked nasal passages, which can reduce mouth breathing.
Suck on Ice Chips: For a sore throat, sucking on ice chips can numb the area, making swallowing less painful and reducing saliva pooling.
Maintain Good Oral Hygiene: Brush your teeth and tongue frequently to help manage saliva and minimize bacterial buildup.

If drooling persists or is accompanied by other severe symptoms like trouble breathing, difficulty swallowing, or a stiff neck, it's important to see a healthcare provider. In rare cases, excessive drooling in adults can signal a more serious neurological issue, though this is uncommon with a typical illness.

Conclusion: The Bigger Picture

Drooling during an illness, while bothersome, is a sign that your body is working hard to fight off infection or protect itself from irritants like stomach acid. From increasing saliva flow to cleanse your mouth to the simple mechanical effects of a blocked nose, the causes are varied but tied to your body's natural defensive systems. By understanding the root cause, you can better manage the symptom and focus on your recovery. For more authoritative information on managing symptoms, you can refer to resources like the MedlinePlus Medical Encyclopedia.

Frequently Asked Questions

Yes, it is common to drool more when you have a cold. This is often caused by nasal congestion, which makes you breathe through your mouth, and a sore throat that can make swallowing painful.

Sickness can cause increased saliva production, known as hypersalivation. This can be a result of infections irritating the mouth and throat, or a reflex triggered by nausea or acid reflux.

To reduce night-time drooling, try sleeping on your back with your head elevated. Using a saline spray to clear nasal congestion can also help you breathe through your nose, and sucking on ice chips can soothe a sore throat.

Yes, acid reflux is a common cause of excessive salivation and drooling. The body produces extra saliva to neutralize stomach acid that has backed up into the esophagus.

While temporary drooling is normal, you should seek medical attention if it's accompanied by difficulty breathing, severe difficulty swallowing, a very stiff neck, or if it doesn't resolve after the illness passes.

Yes, a sore throat can cause drooling in adults. Severe throat inflammation, like with tonsillitis, can make it painful to swallow, leading to saliva pooling in the mouth.

Nausea makes you salivate more as a protective reflex. The increased saliva helps to coat and protect your esophagus and teeth from the damaging stomach acid that could come up if you vomit.