You can identify whether you have bad breath in the following ways: First, you can identify whether there is bad breath by licking the back of your hand with your tongue and smelling it, if there is bad breath there will be an obvious odor. Second, you can put your finger on the throat after rubbing, take out the smell method to determine whether there is bad breath. Third, you can choose a clean piece of gauze into your mouth, stirring with your tongue for a few seconds and then take out to smell whether there is bad breath. Fourth, the two hands together on both sides of the mouth and nose, breathe out and then smell it can also identify whether there is bad breath. Fifth, you can also use a clean cotton thread to identify whether there is bad breath, the cotton thread will be tightened and put into the teeth repeatedly stretched, a few seconds after taking out there is bad breath will exist obvious odor. All of the above methods can identify whether there is bad breath.