What you put in your mouth may affect breathalyzer results

On Behalf of | May 3, 2019 | criminal defense

Recent studies have shown that breathalyzer tests aren’t always accurate. A number of factors can affect the results you get, such as the quality of the breathalyzer or even a hiccup.

But, did you know that something as simple as what you put in your mouth could have a profound impact on whether or not your arrested for a DUI? Here are just a few things you may want to cut out of your routine.

Your diet

In one recent case, a man who was on the popular Keto diet received a false positive result on his breathalyzer test. Experts say this has to do with the way the body breaks down food while in ketosis. Because the liver is charged with breaking down food, the acetone byproduct of the process may be picked up as a breath test.

Less sophisticated breathalyzers can confuse acetone with isopropyl alcohol, causing the test to read a higher blood alcohol content level than the person actually has.


Breath freshening agents, like mouthwash, may hide the smell of alcohol on your breath, but they won’t do any favors for your BAC score. Some breathalyzers may pick up the alcohol in mouthwash, causing your BAC reading to come up as higher than it actually is.


Those who smoke cigarettes regularly typically have a higher level of the compound, acetaldehyde, in their lungs. Some low-cost breathalyzers may be affected by acetaldehyde levels to display a skewed score.

Fighting a false positive

DUI charges carry hefting penalties, including license revocation, costly fines and jail time. Because there are so many things that can throw off a breathalyzer result, it’s a good idea to speak with a professional to determine the validity of the test if you are facing charges.