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How Mouthwash Can Throw Off a Breath Test

After a person has been pulled over on suspicion of driving under the influence, a police officer may ask for the driver to take a breath test. A person can refuse a breath test to avoid completely implicating themselves for a crime, but their refusal can result in immediate suspension of their license. However, should a driver take a breath test, a skilled DUI defense attorney can work to show that the breath test may be flawed.

Mouthwash Affects Your Breath Test

One of the things that can throw off a breath test is when there is the presence of mouth alcohol. A breathalyzer, as a machine, assumes that the breath exhaled into the machine comes from the lungs. The percentage of alcohol in a person's blood is what determines impairment. While a breathalyzer may be able to determine the amount of alcohol in the bloodstream by reading the amount in the lungs, there is no way of determining that the alcohol the machine is reading is from the mouth instead.

If there is any alcohol in a person's mouth or throat, the breath machine will read this as coming from a person's lungs. If a driver has used mouthwash or breath fresheners before the breath test, there is a chance that the breathalyzer reading might be thrown off. When a person burps, any alcohol that may be in their body can be pushed into their mouth and esophagus, throwing off a reading. Therefore there are a number of factors that can cause a breath reading to be much higher than a driver's BAC truly is.

Attorney Virginia L. Landry has this to say about mouthwash and breath tests: "Mouthwash, as well as other items ingested or rinsed, can falsely elevate a breath alcohol reading. Many people will brush their teeth or use mouthwash rinses before leaving a club and starting their drive home. If used right before driving, a common belief is that an officer will not be able to "smell" alcohol. Forensic studies generally agree that after a deprivation period of 15 minutes (California Department of Health Services Regulations, Title 17, section 1219.3), any mouth alcohol (such as mouthwash) will have dissipated. That may be true under a controlled study environment, but there are many "interfering substances" which can falsely elevate a reading: mouthwash is just one of them."

To determine some of the ways that mouth alcohol may have thrown off a blood alcohol content reading in a breath test you may have taken, consult with an experienced DUI attorney from the Law Offices of Virginia L. Landry, Inc.