This might be a strange post, but I find this interesting. Almost everyone has used mouthwash at one point or another in their life. I remember when I was going elementary school, they gave use some pink fluoride mouthwash on Tuesdays. Only thing I can remember about this is that it has weird fruity taste to it. I really do not know if was working or not.
That being the case, how you do know that mouthwash is working. When you put in your mouth and you are moving it around it starts to burn. This burning feeling is it killing the germs in your mouth. After a while (about 30 seconds or less) it burns so much you have spit it out, but the burning feeling does not go away. At this point your tongue and lower gum are numb from the menthol that was used in the mouthwash.
You might not know, but that burning is what indicates that it working. If you did not have that feeling, would ever know if was doing something?
Even the ones that say, “they do not have any alcohol or menthol” still have that burn feeling a little.