It should come as no surprise that one of the greatest concerns for officers is keeping drivers who are under the influence off the road. Drunk driving is incredibly dangerous for everyone on the road.

To this end, officers will pull over anyone who seems to be driving erratically. From there, they will administer a breathalyzer test to ascertain if the suspected driver is intoxicated. While the test is not 100% accurate, officers can still arrest drivers, and charge them with a DUI.

Due to the inaccuracy of the test, it is possible to blow a false positive, which could result in legal fees, impounding fees, and other punishments. Luckily, there are a few steps you can take to prevent false positive results.



Using mouthwash before leaving the house could increase your odds for a false positive result. Many brands of mouthwash contain moderate to high concentrations of alcohol, and it should come as no surprise that swishing any amount of alcohol in your mouth before taking a breathalyzer test is dangerous. While companies are starting to create mouthwash without alcohol, there is still a possibility of alcohol being on the ingredient list, so look before you buy.

It is also worth noting that gum, mints and even cough drops have the potential to offset your results. While it seems like these would freshen your breath and perhaps prevent a poor result from the breathalyzer, it has the opposite effect. Many sugar substitutes can trigger a breathalyzer to read a high alcohol content.


Like many machines that test for the absence or excess of a substance, a breathalyzer must have a basis for its testing. This is known as the machine’s calibration. If the calibration is off, it could result in countless false positives before the error is ever discovered. The people that are charged with the false DUIs must go to court and attempt to prove that the machine was not calibrated correctly at the time of the arrest. Luckily, DUI defense attorneys understand the science of the breathalyzer and will be able to properly argue that the machine was improperly used or handled. Unfortunately, this comes at the cost of stress and loss of time for their client.


Often, medication can interfere with a breathalyzer test and can make it seem like you have been drinking when you have not. Medications that are applied directly inside the mouth have the highest chance of skewing results.

Medicine that is used to relieve toothaches or sores within the mouth are prime suspects. The portable breathalyzer will detect the medicine in your mouth instead of your blood alcohol content, which will result in a much higher reading than normal.

It should be noted that almost all cold and flu medications contain some amount of alcohol that will show on a breathalyzer test. Remedies that include methanol are often the worst offenders. You should always take extra precautions when driving while ill, and driving while under the influence of medication. If you decide to drive after recently taking medication and your driving is affected, you run the risk of being charged with a DUI.

Many diabetics are also in danger of blowing a false positive on a breathalyzer test. This is caused by low blood sugar levels. Diabetics often have higher acetone levels than non-diabetics, which can dramatically alter the readings of the breathalyzer, depending on the age of the machine, because it might distinguish the difference between normal alcohol and ethyl alcohol. If you believe you were unjustly charged with a DUI because of this, be sure to inform your attorney.

It should also be noted that refusing a breathalyzer test is an option in some states. However, in many states, you can be punished for refusing a breathalyzer test. These punishments are usually related to license suspension or a fine. If an officer asks you to take a breathalyzer test, and you are not sure you would pass due to any of the reasons stated above, knowing your state’s laws on the matter could be the deciding factor in making the correct decision.

It does not matter what circumstances caused your wrongful DUI charge. A false positive will inevitably cause you stress, time, and possibly even money. But understanding some triggers for false positives can help you avoid the situation altogether. And in the unfortunate situation that you or a loved one have been charged with a false DUI, find and call a local DUI defense lawyer.