Bad breath is mainly due to poor oral local hygiene environment caused by a long period of time without serious brushing and rinsing, and never go to the hospital for ultrasonic cleaning treatment, such people’s teeth and between the teeth will accumulate a large number of tartar, food debris and soft scales, these substances in the mouth for a long time, will be their own corruption of the odor, resulting in bad breath when people open their mouths to speak. The bad breath may also be caused by fire in the body, commonly in people with strong stomach fire and liver fire, strong stomach fire is mainly like to eat greasy, sweet and thick food caused by long-term food accumulation, so that the food in the stomach for too long in the memory of the stomach fire rise, which causes the mouth to appear sour taste.