Can I use mouthwash before my morning drive? Help Center › Category: General Support › Can I use mouthwash before my morning drive? 1 Vote Up Vote Down IDNJ Support Staff Can I use mouthwash before my morning drive? 1 Answers 1 Vote Up Vote Down Best Answer IDNJ Support Staff Most likely the device will register alcohol if the mouthwash has alcohol in it. We advise you not to eat, drink or smoke for at least 5 minutes before the test, and do not use mouthwash for at least 10 minutes before the test.