If alcohol in mouthwash can make you fail a breathalizer or what about a inhailor from asthma?

Alcohol in mouthwash may cause you to fail a breathalyzer test because the residual alcohol remains in your mouth for up to 15 minutes after using. The breathalyzer will pick up this residual alcohol in your breath and not differentiate whether it came from mouthwash or beverages. You should never take a breathalyzer test within 15 minutes of taking mouthwash or an alcoholic beverage in order to let the residual mouth alcohol dissipate.

Mouthwash can cause a positive result on an ETG test. Whether or not an asthma medication could do the same thing would depend on whether it contained alcohol, how often it was used, and when the test was give.