What Causes Foaming at the Mouth?

Foaming at the mouth is a physical symptom that occurs when excess saliva mixes with gases or air, which creates the foamy sensation and is rarely found by itself, however, unintentional foaming can be a sign of a serious medical condition that may require emergency care.

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What Causes Foaming at the Mouth?

Foaming at the mouth is something that we’ve been conditioned to expect of people in certain conditions, but foaming at the mouth is very serious. If bubbly saliva spills out of someone’s mouth, it may require medical attention as it is usually associated with problems with the central nervous system or life-threatening complications like a coma.

Some of the most common causes of foaming at the mouth include:

Drug Overdose

If somebody consumes excess drugs or toxins, this can contribute to an overdose. The nature of the drugs taken may contribute to different types of foaming. For example, someone who has overdosed on heroin may display what is known as a “foam cone” coming out of the mouth and the nostrils, which is a recognized consequence of anoxia, when your body or brain loses its oxygen supply and can follow a pulmonary edema, where fluid leaks into the lungs. 

Additionally, a severe overdose can result in seizures which causes salvia, or drooling, to pool in the mouth, which may be pushed through the lips or clenched teeth. When the lungs are not working as they should this results in fluid building around the organ, starving the cells of oxygen and causing a build-up to mix with the fluid, resulting in a frothy mucus, either light pink in color or tinted with blood, which spills out of an individual’s mouth.


People who have conditions that cause seizures such as epilepsy can experience different types of seizures with unique symptoms, but one type of seizure is associated with foaming at the mouth, which is a tonic-clonic seizure. While this type of epilepsy can cause foaming at the mouth, foaming is a symptom that is wrongly assumed to be in every type of epileptic fit. 

A tonic-clonic seizure, also known as a Grand Mal seizure, comprises two phases: tonic activity and clonic activity. The clonic activity involves jerking movements, and the tonic activity is strong tonic spasms of the muscles, which forces air out of the lungs and is where saliva can come out of the mouth. 

In addition to convulsions, seizures can also cause incontinence, loss of consciousness, and frothing at the mouth. Foamy saliva occurs in this situation because the mouth is forced closed. When the mouth is forced closed, this stimulates the saliva glands which makes you produce extra spit, and when the mouth opens again after the seizure, the frothy saliva comes out. 

Foaming at the mouth can also occur following a seizure that has been provoked, for example, after being tased. Up for epilepsy and seizures include brain surgery and antiepileptic medication, such as narrow-spectrum AEDs and broad-spectrum AEDs.


Rabies is a virus that affects the central nervous system and is carried by infected warm-blooded animals. Common carriers of rabies include bats, wolves, foxes, and raccoons but everyday animals like dogs and cats can also carry it but are less commonly affected. 

If an animal with rabies bites or licks a scratch or open wound, this could impact you. Foaming at the mouth is one of the most commonly known symptoms of rabies because the virus attacks the nervous system. 

Because the person or animal is not able to swallow their saliva, the foam comes out of the mouth. Other symptoms include convulsions, agitation, biting, and lost appetite. There is no way to treat rabies, but in an emergency room, a tetanus shot may be administered, but it’s essential to mitigate the effects of rabies by having a shot approximately every 10 years.

Heart Attack

A heart attack, also known as myocardial infarction, is a very common occurrence, with one happening approximately every 40 seconds. Symptoms can be severe or mild and differ from one person to the next, such as lightheadedness or shortness of breath. 

If an individual experiences chest pain that preempts a heart attack, the heart attack causes the lungs to become congested. Acute pulmonary edema can cause foaming at the mouth, which can cause a patient to choke to death on their own secretions.

Foaming at the Mouth While Sleeping

If you are experiencing foaming at the mouth while you are asleep, this is usually the result of dry mouth, which can be a short-term response to a number of conditions, such as: 

  • Stress.
  • Dehydration. 
  • Nervousness. 
  • Mouth breathing. 

Additionally, experiencing dry mouth might be a symptom of oral or bodily conditions such as:

  • Sjogren’s Syndrome, an autoimmune disorder. 
  • Diabetes. 
  • Oral thrush. 

If you are experiencing foamy saliva while you are asleep, it’s very likely because you are sleeping with your mouth open, which causes saliva to flow out of the mouth resulting in “snail tracks” on your cheeks. You can prevent these by doing the following: 

  • Sleep on your back. 
  • Prop your head up. 
  • Breathe through your nose.

Treatment for Foaming at the Mouth

Depending on the cause of the foaming of the mouth, there may be specific treatment methods. Foaming of the mouth arising from drug overdoses can be treated by an injection of naloxone. 

  • Epileptic and non-epileptic seizures can be treated with medication or psychotherapy.
  • Rabies can be prevented with vaccines or other injections
  • A heart attack is treated with emergency medical treatment.

When to See a Doctor?

It’s important to note that if you are experiencing foaming at the mouth arising from any of the above conditions, you must get in contact with a doctor straight away. Your doctor can determine the best course of action based on what is causing the foaming at the mouth before treating the underlying cause.

Key Takeaways

Foaming at the mouth is very uncommon, but can be associated with serious health complications like overdoses, seizures, rabies, and heart attacks. If anybody starts to foam at the mouth, it’s important to make sure the airways are clear and the individual is on their side, so the foam can escape. 

If left untreated, the conditions resulting from foaming tend to lead to serious complications such as organ failure or death. It is vital to have immediate medical treatment to deal with the underlying medical condition.


Content on the DrHouse website is written by our medical content team and reviewed by qualified MDs, PhDs, NPs, and PharmDs. We follow strict content creation guidelines to ensure accurate medical information. However, this content is for informational purposes only and not a substitute for professional medical advice, diagnosis, or treatment. For more information read our medical disclaimer.

Always consult with your physician or other qualified health providers about medical concerns. Never disregard professional medical advice or delay seeking it based on what you read on this website.

If you are experiencing high fever (>103F/39.4C), shortness of breath, difficulty breathing, chest pain, heart palpitations, abnormal bruising, abnormal bleeding, extreme fatigue, dizziness, new weakness or paralysis, difficulty with speech, confusion, extreme pain in any body part, or inability to remain hydrated or keep down fluids or feel you may have any other life-threatening condition, please go to the emergency department or call 911 immediately.



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