Tooth clenching is an abnormal chewing movement. Tooth clenching can develop in childhood or in old age, and the etiology is not exactly the same. In children, during the immature and infantile stage of development, the management function of brain cells is poor, and clenching of teeth can occur in the dream state of eating. Some affected children have parasites that irritate the gastrointestinal tract, and peristalsis of the gastrointestinal tract causes movements such as clenching and chewing. The appearance of such a problem is a sign that there are some aspects of the child’s body and mind that are problematic and require a detailed examination, diagnosis and differential diagnosis by a professional pediatrician, followed by the development of a reasonable treatment plan. The appearance of chewing movements during the day in the elderly due to other diseases, especially gastrointestinal diseases and brain diseases, is a sign that the brain is out of control. The appearance of clenching and chewing movements at night during sleep state indicates problems in the gastrointestinal tract and the neurological control system of the brain. After this phenomenon occurs, you must go to a professional physician for examination and diagnosis, give a reasonable explanation and carry out effective symptomatic treatment. Do not think that clenching is a trivial matter, but when the chewing action of clenching is not normal, it reflects that the body has some kind of disease, which belongs to the abnormal management of the nervous system of the brain, so patients must consult a professional physician for treatment to receive good results.