Does Mouthwash Have EtG in It? Understanding the Link to Positive Alcohol Tests

October 9, 2025 •

4 min read

Ethyl glucuronide (EtG) is a metabolic byproduct of ethanol and is not an ingredient in any consumer product, including mouthwash. The question, however, isn't whether mouthwash contains EtG, but rather, whether the use of certain mouthwashes can cause a positive result on a sensitive EtG test.

Quick Summary

This article explains that EtG is a metabolite, not a mouthwash ingredient, but that some mouthwashes containing ethanol can lead to a positive EtG test. It details how this occurs, the difference between alcohol-based and alcohol-free products, and strategies to avoid false positives, especially for individuals in alcohol abstinence programs.

Key Points

EtG is a Metabolite: Ethyl glucuronide (EtG) is not an ingredient in mouthwash but is a byproduct of the body metabolizing ethanol.
Alcohol-Based Mouthwash is the Culprit: Many antiseptic mouthwashes contain ethanol (ethyl alcohol), which is the source of the problem for EtG testing.
Absorption Causes Metabolites: Even without swallowing, the ethanol in mouthwash can be absorbed through the oral mucosa and metabolized into detectable EtG.
EtG Tests are Highly Sensitive: EtG tests can detect low levels of alcohol exposure from non-beverage sources, like mouthwash and hand sanitizer.
Standard Cutoffs Reduce Risk: Higher cutoff levels, often used in legal monitoring, are typically high enough to avoid false positives from mouthwash use, but lower cutoffs can be problematic.
Alcohol-Free is the Safe Option: Choosing alcohol-free mouthwash is the recommended strategy for individuals who must maintain strict alcohol abstinence.
Wait Time is Crucial for Breath Tests: The effect of mouthwash is different for breathalyzers, where alcohol dissipates from the mouth within 15-20 minutes.
Incidental Exposure is Broader than Mouthwash: Other products like hand sanitizers and some medications can also contribute to incidental ethanol exposure and positive EtG tests.

EtG vs. Ethanol: Differentiating the Compounds

To understand why mouthwash can trigger a positive EtG test, it's crucial to understand the fundamental difference between the two substances. EtG, or ethyl glucuronide, is a direct biomarker of ethanol consumption. It is a non-volatile, stable, and water-soluble compound created in the body when the liver processes ethanol. EtG is not present in the mouthwash itself.

Ethanol, or ethyl alcohol, is the key ingredient in alcoholic beverages and is also found in many antiseptic mouthwashes. The concentration can vary significantly, with some antiseptic rinses containing as much as 8–26% ethanol by weight. It is this ethanol, when absorbed by the body, that the liver metabolizes, creating detectable EtG in urine for a prolonged period.

The Pharmacology of Mouthwash and EtG Detection

When a person uses an alcohol-containing mouthwash, several things happen that can lead to a positive EtG test, even if none of the product is intentionally swallowed.

Absorption and Metabolism

Oral Absorption: The oral mucosa has a rich blood supply, allowing for easy and rapid absorption of ethanol. When someone swishes mouthwash, a small amount of ethanol is absorbed directly into the bloodstream through the lining of the mouth and throat.
Unintentional Ingestion: It is nearly impossible to prevent all mouthwash from trickling down the throat and being unintentionally ingested. Even small, repeated exposures contribute to the body's overall ethanol load.
Hepatic Metabolism: The absorbed and ingested ethanol is metabolized by the liver. In this process, a portion of the ethanol is conjugated with glucuronic acid, forming EtG.
Detection Window: Unlike a breathalyzer, which detects alcohol shortly after use, EtG can be detected in urine for an extended period after ethanol exposure—often up to several days, depending on the exposure level and individual metabolism. This prolonged detection window is why EtG tests are used in zero-tolerance monitoring programs.

Studies on Mouthwash and EtG Levels

Scientific studies have confirmed that incidental exposure to alcohol-containing products like mouthwash can produce detectable levels of EtG. For example, a study conducted by the United States Drug Testing Laboratories (USDTL) showed that using an antiseptic mouthwash with 21.6% ethanol multiple times over an eight-hour period resulted in detectable concentrations of EtG and ethyl sulfate (EtS). However, the levels produced by this incidental exposure were significantly lower than what would be expected from intentional alcohol consumption.

The Importance of Cutoff Levels

Most laboratories and programs that rely on EtG testing utilize specific cutoff levels to differentiate between incidental exposure and deliberate consumption. Many court-ordered monitoring programs use a standard cutoff level of 500 ng/mL to avoid false positives. Incidental use of mouthwash typically results in EtG levels well below this threshold. However, more sensitive programs may use a lower cutoff, such as 100 ng/mL, which makes the risk of a positive result from mouthwash much higher.

Comparison of Alcohol-Based vs. Alcohol-Free Mouthwash


Feature	Alcohol-Based Mouthwash	Alcohol-Free Mouthwash
Ethanol Content	Often contains 8-26% ethanol.	Contains no ethanol.
EtG Risk	Can result in detectable EtG, leading to a positive test, especially with highly sensitive cutoffs or repeated use.	Does not contribute to EtG formation and does not pose a risk for a positive EtG test.
Sensation	Often provides a stinging or burning sensation associated with "killing germs."	Offers a milder, less intense rinsing experience.
Active Ingredients	Ethanol is a primary active ingredient.	Uses alternative antimicrobials like cetylpyridinium chloride (CPC) or essential oils.
Recommended For	General use for individuals without alcohol-monitoring requirements.	Individuals in abstinence programs, those with dry mouth, or anyone avoiding alcohol exposure.

Avoiding False Positives from Incidental Alcohol Exposure

For anyone in a zero-tolerance program or subject to sensitive alcohol testing, avoiding a false positive requires a proactive approach. It is not just about mouthwash; many common products contain ethanol.

Products to be aware of:

Antiseptic Mouthwashes and Breath Sprays: Many popular brands like Listerine and Scope contain significant amounts of ethanol.
Hand Sanitizers: Alcohol-based hand sanitizers are a significant source of incidental ethanol exposure, particularly with frequent use.
Over-the-Counter Medications: Some cough syrups, cold preparations, and liquid medicines list ethanol or alcohol as an ingredient.
Foods: Certain foods, particularly those with alcohol flavorings, or items that contain high levels of fermentation, can contain trace amounts of alcohol, though typically not enough to trigger a positive test.

Steps to Prevent a Positive Test:

Read Labels Carefully: Always check the ingredients list on personal care and over-the-counter products for terms like "ethanol," "ethyl alcohol," "SD alcohol," or "denatured alcohol".
Switch to Alcohol-Free: Opt for alcohol-free alternatives for mouthwash and hand sanitizer to completely eliminate the risk of incidental ethanol absorption.
Inform Testing Personnel: If there is any concern, inform the testing administrator about any recent use of products containing alcohol.
Maintain Records: Keep a record of the products you use, especially if you are regularly tested.

Conclusion

To answer the question, no, mouthwash does not inherently contain EtG. Instead, EtG is a metabolite that the body produces after processing ethanol. Consequently, using an alcohol-based mouthwash can result in the formation of EtG, potentially leading to a positive result on a sensitive EtG test. The risk depends on several factors, including the mouthwash's alcohol content, the frequency of use, and the specific cutoff level used by the testing facility. For individuals in abstinence programs or those who must undergo frequent alcohol monitoring, the only safe and reliable strategy is to switch to alcohol-free products. This simple precaution can prevent unintended exposure and the stress and complications that a false positive result can cause. As evidenced by numerous studies, understanding the sources of incidental alcohol exposure is a critical part of successfully navigating zero-tolerance environments.

For more detailed research on the subject, a study published in Substance Use & Misuse offers further insights into this topic(https://scholarlycommons.henryford.com/womenshealth_articles/49/).

Frequently Asked Questions

Yes, using an alcohol-based mouthwash can cause a positive result on an EtG test. The test detects ethyl glucuronide, a metabolite of ethanol, which your body produces after processing the alcohol contained in the mouthwash.

No, alcohol-free mouthwash does not contain ethanol, so it will not cause your body to produce EtG. This makes it a safe alternative for individuals in alcohol abstinence programs.

While EtG from typical alcohol consumption can be detected for several days, the concentration from mouthwash is usually lower. The detection window for incidental exposure is shorter, but it can still show up on a sensitive test, especially if used repeatedly.

It is possible. Because EtG tests are very sensitive, even a small amount of absorbed ethanol from a quick rinse can be converted to EtG and trigger a positive result, depending on the test's cutoff level.

Test cutoffs are the thresholds used to distinguish between incidental exposure and intentional consumption. Standard cutoffs (e.g., 500 ng/mL) are usually high enough to ignore mouthwash use, but more sensitive programs with lower cutoffs (e.g., 100 ng/mL) are more likely to detect it.

Inform the testing personnel of the situation immediately. Also, be sure to note the time and brand of mouthwash used. They may be able to administer a confirmatory test or consider the potential for incidental exposure when interpreting the result.

Yes, other common products can lead to incidental ethanol exposure. These include alcohol-based hand sanitizers, certain over-the-counter cough syrups, and some breath sprays.