What Drugs Cause Foaming at the Mouth?

foaming at the mouth

Approximately 37 million Americans say they regularly use illegal drugs. Besides overdoses, this leads to myriad social and personal problems, not the least of which are health issues and related side effects.

These include everything from lack of energy and motivation to minor or severe changes in behavior, and they vary based on the individual and type of drug being abused.

However, there are symptoms of substance use, such as foaming at the mouth, that are particular to certain drugs. Once you understand what these are, you can more easily identify potential underlying causes. 

This article covers the different causes of foaming at the mouth. These include medical conditions as well as legal and illicit factors. Keep reading to learn more about how to respond to these situations.

What Causes Foaming at the Mouth?

At a very basic level, foaming at the mouth occurs when excess fluid in the lungs or mouth mixes with air. This causes the moisture to froth.

Besides illegal drugs, various conditions are linked to foaming at the mouth. Here are the main ones to consider.


Rabies, a viral infection that can be transmitted to humans through animal bites, is notorious for causing foaming at the mouth. It does so by affecting the central nervous system and the brain.

One of the side effects of rabies’s impact on the body is that it can become difficult to swallow. This, in turn, causes saliva to accumulate in the throat and mouth, which can lead to foaming.


Seizures are bursts of electrical activity in the brain. They result from epilepsy or other similar conditions.

A common symptom of seizures is foaming at the mouth. This happens for similar reasons as rabies: muscle spasms. In particular, tonic-clonic or grand mal seizures can involve violent muscle spasms.

This can force air out of the lungs and the throat to constrict. Again, the accumulation of saliva mixed with emitted air can produce a foaming occurrence.


Another common cause of foaming at the mouth is poisoning. This involves consuming, inhaling, or otherwise being exposed to household cleaners, personal care products, pesticides, and lawn products that have adverse effects on the body.

Poisoning can result from exposure to industrial chemicals as well. Also, certain plants and mushrooms are toxic to humans. Poisoning can also result from various medications as well (more on that below).

Poisoning affects the central nervous system, which controls saliva production. This can lead to foaming of the mouth as a symptom.

Heart Conditions

Congestive heart failure is another condition that can cause foaming at the mouth. Since the heart cannot pump efficiently, fluid begins to leak from the veins and settle in the surrounding tissues.

This often causes fluid buildup in the lungs, known as pulmonary edema. In severe cases, the individual’s lungs become so full of fluid that they begin foaming at the mouth while attempting to breathe.


Finally, foaming at the mouth is sometimes a symptom of stroke. For this reason, strokes that lead to this symptom are often confused with seizures.

To complicate things further, strokes can also trigger seizures. That is because the lack of blood flow interferes with the brain’s electrical signals.

In general, this influences muscle control in the throat, mouth, and face. It is the same reason that stroke sufferers often experience drooling or teeth clenching.

What Drugs Cause Foaming at the Mouth?

Foaming at the mouth is also a serious symptom of drug abuse. It is often accompanied by other symptoms, though not always. Common ones include seizures, vomiting, limp or unresponsive body, cold skin, and appendages turning purple.

There also are myriad medications and illicit drugs that can cause foaming in the mouth. Here are the main ones to be aware of.

Heroin and Opioids

Heroin and opioids are the most common culprits of drugs that can cause foaming at the mouth. They are sedatives that suppress respiratory functions. This results in excess saliva production that can lead to mouth frothing.

While this can happen with the user is conscious (yet sedated), it can also lead to unconsciousness. In this instance, immediate medical attention is necessary.


Amphetamines are powerful stimulants that impact the central nervous system. They do so by increasing the release of neurotransmitters, including dopamine, in the brain, spinal cord, and elsewhere in the body.

Besides being associated with positive moods and feelings, dopamine is involved in promoting muscle movement. This often leads to jitteriness and an increased propensity for physical activity.

It also affects the muscles of the mouth and face, as well as salivary glands. One or the combination of these factors results in increased saliva production, which can produce a foam-like appearance in some users.


Cocaine is also a stimulant that can lead to foaming at the mouth. Though it comes from a different source and has a distinct chemical makeup, cocaine affects the brain in very similar ways as amphetamines. It increases the level of circulating neurotransmitters, including dopamine, serotonin, and norepinephrine.

Cocaine is extremely powerful, but its effects do not last as long as amphetamine. In fact, it can begin to wear off in as little as an hour after usage. For this reason, foaming at the mouth as a result of cocaine use will almost always happen soon after consumption.


Ecstasy is a stimulant that also produces a rush of good feelings by impacting the production of neurotransmitters. While a common side effect of ecstasy use is dry mouth, it sometimes can result in foaming at the mouth as well.

This happens when users feel overly anxious, confused, or paranoid. It is in part attributable to the clinching of the teeth and failure to swallow. These results (versus dry mouth) are more common when people take exceedingly large doses of ecstasy.


Along with opioids, alcohol is one of the few sedatives on this list that can cause foaming of the mouth. While rare, it can occur and for the same reasons as heroin or opioids.

These instances usually involve very large quantities of alcohol. Also, they almost always accompany pulmonary edema – where fluid leaks into the lungs – or heart attack.

Drug Overdoses

Drug overdoses of any type can lead to foaming at the mouth. This can result from either muscle spasms – much like those experienced from poisoning – or loss of muscle control. The latter cause often stems from the person’s heart rate and breathing beginning to slow, causing them to not swallow.

Regardless of the physiological cause, drug overdoses that lead to foaming at the mouth are extremely dangerous. It is important to seek professional medical attention in these instances.

Prescription Drugs

Finally, some prescription drugs can cause foaming of the mouth as a side effect. This often involves taking them in very large doses.

Common medications that can lead to this are antipsychotics, like haloperidol and risperidone. Benzodiazepines, like lorazepam and diazepam, also can lead to frothing at the mouth. Medications for treating seizures, like phenobarbital and phenytoin, can cause it as well.

What Are the Treatments of Foaming at the Mouth?

Treatments for frothing at the mouth depend on the conditions that cause them. For instance, seizures can be treated with antiepileptic or similar medications. In some cases, surgery or other types of medical interventions can help prevent them.

Rabies can be prevented using vaccines. It can also be treated during the early stages of infection through a series of shots. Once rabies infection sets in, there’s no effective treatment for it.

Hospitalization is often necessary for poisoning. This depends on the nature of the poison, level of exposure, and other symptoms. 

Medical professionals can treat opioid and other drug overdoses using different medications. These include naloxone, an opioid antagonist.

It binds to opioid receptors, reversing the effects of dangerous drugs like heroin, oxycodone, and morphine. It also can block further activation of nerve cells in the brain by the substance.

While there are often no warning signs for congestive heart failure or stroke, seeking immediate medical attention is imperative. Foaming at the mouth is a symptom of serious conditions that are often life-threatening.

Finally, an effective treatment of opioid side effects, including foaming at the mouth, is recovery. Finding the right program and treatment regimen can be vital to success. Quality rehabilitation facilities will couple medical and substance abuse treatment with mental health services for co-existing conditions.

Learn More About Drug Abuse Side Effects

Now that you know what conditions and drugs cause foaming at the mouth, you have a better understanding of their dangers and how they affect your body. If you or someone you know is struggling with serious addiction issues, there’s help.

At both our Phoenix location and Scottsdale campus, Purpose Healing Center offers the highest quality treatment in the behavioral health care industry. We provide a customized plan for addiction recovery and to address co-occurring mental health concerns, and we work with most insurance plans.

Reach out to us today to learn more about opioid addiction recovery or other treatment options.