DUI FAQ: Does Mouthwash Affect a Breathalyzer Test?

June 4, 2019

If you have been charged with driving under the influence but did not drink before driving, you are likely both frightened about facing drunk driving penalties and confused about how the breathalyzer test detected alcohol in your system. Can you fail a breathalyzer test from mouthwash? Get the facts, then seek DUI assistance from a qualified criminal defense attorney.

The Impact of Mouthwash on a Breathalyzer

While a breathalyzer test is designed to analyze the alcohol content of air deep within the lungs, this air must pass from the alveoli and up through the trachea before exiting through the mouth for testing. When this occurs, the mouthwash alcohol content can increase the alcohol content of this so-called alveolar air and create a false high reading, leading to a DUI charge.

Factors That Cause Breathalyzer Error

Mouthwash isn’t the only substance that can cause a false breathalyzer reading. Beyond mouthwash and breathalyzer test, this screening can be affected by recent consumption of a cough drop, menthol cigarette, chewing gum or countless other things.

Residual mouth alcohol gets trapped within crevices of the mouth as well as around piercings and fillings. In addition, individuals who have a stomach condition called GERD often expel digestive gas that can cause a high reading. Certain medications, including asthma prescriptions, can lead to a high blood alcohol level even without intoxication.

Steps To Take After a False Breathalyzer

If you think mouth alcohol is the source of your DUI charge, ask for a retest. A breathalyzer reading that drops significantly after 10 to 30 minutes often signifies the presence of mouth alcohol. Cooperate with the investigation, but immediately seek legal advice and gather any potential evidence that supports your assertion of a false reading.

Penalties for DUI include steep fines, loss of license and even jail time. A traffic offense ticket lawyer can advocate on your behalf in court if you believe you have been erroneously charged with a DUI. He or she will investigate the type of equipment used, your habits and activities on the day of the incident and the research studies behind false positives to mount a defense.