An increasingly popular but still unproven techology involves testing saliva taken from mouth swabs. Saliva testing has the advantage of being less invasive than either urine or blood tests. So far, tests have shown them to be inconsistent and unreliable when it comes to detecting marijuana, but that hasn't stopped them from being used. The sensitivity of saliva tests hasn't been clearly established, but may range from a few hours to a day or more. While it might be supposed that mouthwash is a helpful defense against saliva tests, this isn't necessarily the case, since the tests are supposed to detect drug residues that are exuded from the body's internal mouth tissues into the saliva.