No, Listerine will not help you pass a drug test, especially a swab test. Listerine is a mouthwash that is primarily used for oral hygiene purposes such as freshening breath and reducing plaque. It does not have the ability to alter or mask the presence of drugs in your system. If you are concerned about passing a drug test, it is best to refrain from drug use and allow sufficient time for the substances to naturally clear out of your body.