Bad breath, in fact, is a relatively common clinical symptom, and there are several ways to measure bad breath. First, the first is during the recent epidemic, almost all of us will wear masks, when we repeatedly wear the mask smell the mask, whether there will be a significant odor, you can detect whether you will have obvious bad breath phenomenon, this is now a relatively simple method. Of course, you can also choose other methods, for example, in our previous normal social interaction can observe whether others in close proximity to talk with you will have a clear sense of disgust. Of course, the best way is to find a few relatively close people, direct smell, to see if they have obvious bad breath phenomenon. You can also find a suitable size, clean bottle at home, blow in the bottle, and then smell the bottle to see if there will be obvious bad breath smell. Finally, you can observe whether there is obvious tartar in your mouth and whether there is obvious fatty tongue, which may be clinical manifestations of bad breath.