What Happens If You Swallow Listerine?

Written & Reviewed by Dr David Chen

If you swallow Listerine whether intentionally or accidentally, there will be adverse effects because it is not a beverage. It is an antiseptic mouthwash that is meant to freshen your mouth, eliminate bacteria, and reduce plaque. After using it, you’re not supposed to drink it because you need to spit it back out.

Listerine - Cool Mint

Listerine is not food nor was it ever meant to be. Have you ever heard of anyone having a glass of it while eating steak? No because it doesn’t taste like wine nor are you supposed to swallow it.

We will explain what the consequences are for accidentally drinking it. Hopefully you’re not trying to intentionally trying to drink it right?

Adverse effects

The most notable side effect from swallowing Listerine is intoxication, which primarily stems from its high alcohol content. Yes, this alcohol based mouthwash contains 21.6%-26.9% alcohol by volume. The only exception would be their “zero alcohol” line of mouth rinses.

We are equally as surprised as you are but a study from Food and Chemical Toxicology found that most of the adverse effects are due to the alcohol. There is limited evidence of the other ingredients causing other types of side effects. Only the alcohol content can potentially exceed the acceptable daily intake (ADI), while the other ingredients are unlikely to do so.

Other potential side effects

While it is unlikely for you to exceed the acceptable daily intake from the other ingredients in Listerine, it is still possible if you swallow enough of it. Nonetheless, it is still useful to know what can potentially happen if you overdose on the other ingredients in this mouthwash.

Side effects from overdosing on each ingredient:

Overdose symptoms:

  • Burning sensation in the mouth/throat
  • Abdominal pain
  • Spontaneous vomiting
  • Giddiness
  • Ataxia
  • Disorientation followed by loss of consciousness.

Overdose symptoms:

  • Blood in the urine
  • No urine output
  • Rapid breathing
  • Shallow breathing
  • Abdominal pain
  • Diarrhea
  • Nausea¬†and¬†vomiting
  • Heart palpitations
  • Rapid heartbeat
  • Convulsions
  • Dizziness
  • Tremor
  • Unconsciousness
  • Unsteady walking

Overdose symptoms:

  • Decreased or no urine output
  • Eye irritation – burning, redness, tearing, pain, light sensitivity
  • Loss of vision
  • Ringing in the ears
  • Throat swelling
  • Collapse
  • Low blood pressure
  • Difficulty breathing, no breathing, rapid breathing
  • Agitation, confusion, hallucinations
  • Coma
  • Deafness
  • Dizziness
  • Drowsiness
  • Headache
  • Fever
  • Seizures
  • Nausea and bloody vomiting

Overdose symptoms:

  • Hyperactivity
  • Burning nose
  • Ataxia
  • Hypersalivation
  • Respiratory distress
  • Lethargy
  • Hypothermia
  • Coma
  • Death

All four of these are essential oils and they’re the “active” ingredients in the mouthwash. Once again, it is unlikely for you to experience these symptoms but it can happen if you accidentally swallow enough of it.

How much listerine is lethal?

Drinking an entire 1 liter bottle of Listerine can be lethal, meaning you will die and never wake up ever again. That information is extrapolated from the University of Kansas’s alcohol facts.

Since the major adverse effect of ingesting it stems from its alcohol content, the lethality of it would be similar to ethanol overdose. According to the University of Kansas, 21 shots (1.5 oz each) of 30% alcohol will raise your BAC (blood alcohol) to 0.42 which can be lethal.

The original Listerine that comes in the yellow color is 29.6% alcohol which is fairly close to the 30% reference point above.

  • 21 shots of 1.5 oz = 31.5 oz
  • A 1L bottle of mouthwash is 33.8 oz

Therefore, drinking the entire typical bottle of the mouthwash would put you right above the limit that may lead to your death.

Caution: Please be aware that your bodyweight influences how much you can take. Also, you don’t need to ingest the entire bottle to already have severe symptoms so please try your best to not swallow any of this accidentally!

What to do if you swallow it

According to the warning label on the bottle, you should call poison control if you accidentally swallow more than what is used for rinsing.

Here is a screenshot of the warnings taken directly from the Listerine website:

Listerine warning label
Warning label

It is interesting in that the exact wording says “if more than used for rinsing”, which implies that if the exact specified amount for rinsing was used, you should be okay.

However, if you used more than their recommended amount then you’d need to contact a poison control center. Do you know what that quantity is?

Recommended amount for rinsing

The official rinsing directions are to use 20 ml (2/3 fluid oz or 4 teaspoons) for 30 seconds twice a day, morning and night.

It explicitly says DO NOT SWALLOW.

Does this apply to their zero alcohol products?

Theoretically, their mouthwashes with no alcohol in them should be safer than their alcohol based counterparts. Since there is zero ethanol, you shouldn’t be experiencing intoxication or exceed the lethal limit of getting a BAC above 0.4

Despite the more positive news, the warning label for Listerine Zero rinses still says to contact poison control if you swallow more than what you’re supposed to use for rinsing. The wording remains the same regardless of if there is alcohol in there or not.

Nonetheless, the current trend and preference by the general public is towards the non-alcoholic rinses. That would be the safer choice in our opinion.

Who in their right minds would drink this?

Interestingly, studies have observed that there are individuals who intentionally drink Listerine specifically for the alcohol buzz. It has most commonly been observed in hospital, prison, and military establishments whenever the availability of alcohol has been restricted.

Other times it can be from alcoholics who are desperate to get their hands on a beverage but can’t, may turn to drinking mouthwash. It really is quite unfortunate.

Nonetheless, we do not recommend ingesting any of this. We stand by the warning label of what the manufacturer says.


According to Listerine, if you accidentally swallow more than the amount used for rinsing, you should contact a poison control center. The most prominent adverse effect is inebriation which comes from the alcohol in the rinse.

However, if you swallowed their non-alcohol rinse you may not get intoxicated. Although you should still contact poison control if you ingest it.


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