No, mouthwash is not effective in fooling oral drug tests. Various types of mouthwash such as Listerine have been used by people to remove the smell from the mouth. Well, all it does is to kill bacterias presents in the mouth and helps to remove the bad odour due to residue left in the mouth after smoking. However, for some people, mouthwash trick works which is just a matter of luck but it cannot be used as an effective measure to pass oral drug tests.

When police officers carry out an oral drug test on the roadside, all they are looking for the presence of byproducts of drugs in the body. A saliva test is conducted in which could be used to indicate whether a drug is present in the body or not. The actual drug components are not tested in this test but its byproducts generated after the processing of drugs in the system are tested. As Listerine and other mouth wash contain alcohol so it should not be used if hide the presence of alcohol as oral alcohol test will easily detect the presence of alcohol in your body.

However, for the case of smoke test, hydrogen peroxide or mouthwash could be used to pass oral test. All you need to do is to take a low concentration hydrogen peroxide of mouthwash in your mouth along with a little amount of water. The road-side oral tests are not that sensitive so there are high chances that you will be able to pass the smoke test using mouthwash or hydrogen peroxide. Care should be taken that you must spit hydrogen peroxide outside without swallowing it. Although low-concentration of hydrogen peroxide doesn’t cause any damage, if it is taken in high concentration then it could cause health problems to your body.

However, it is not possible to pass every type of oral test using mouthwash. So, it is recommended to use other effective ways to pass an oral test.