It is often said that “toothache is not a disease but a pain that kills”, which reflects the great impact of toothache on human health. There are many causes of toothache, and both odontogenic and non-odontogenic diseases can cause it. In odontogenic diseases, the pain can be dentin allergy, pulp pain, periapical pain, or periodontal pain. In non-dental diseases, inflammation of adjacent tissues, tumors, neurological diseases, systemic diseases, etc. can be manifested as toothache. 1, dentin allergy: when brushing teeth, eating hard objects or cold, hot, sour, sweet and other stimulation pain, this pain is short-lived, when the cause of stimulation cloud removed the soreness can disappear quickly. The common causes are caries, wedge-shaped defect, abrasion and so on. 2.Caries: especially when deep caries with pulp filling, the affected tooth feels pain when encountering cold, hot, sour, sweet stimulation or food embedded, and at the same time there is color change or obvious cavity formation. 3.Acute pulpitis: when the caries treatment is not timely and continues to develop near the pulp, spontaneous, paroxysmal, radioactive pain will appear, and it cannot be localized, and the pain will increase when encountering cold or hot stimulation or resting at night. 4.Acute and chronic periapical inflammation: the development of pulpitis can lead to periapical inflammation, manifested as continuous jumping pain, tooth elongation or floating sensation, unable to chew food, can clearly point out the affected tooth, insensitive to hot and cold stimulation. When the lesion develops further, it can even cause osteomyelitis of the jaws, tooth loss and loss, or the affected tooth as a potential lesion, when the body resistance decreases, it can cause complications such as bacteraemia. 5, periodontal area pain: common diseases are interdental papillitis, acute periodontal abscess, mostly manifested as persistent dull pain, accompanied by red and swollen gums, bleeding and pus overflow, and even loose teeth or gum atrophy. 6, hidden tooth crack: refers to the crown surface of the non-physiological small cracks, often not easy to be detected. The crack often penetrates into the dentin structure and can cause severe pain from hot and cold stimulation or fixed-point chewing. 7, tooth fracture: often caused by external office force impact, can be manifested as crown fracture, root fracture, crown-root joint fracture. 8, pericoronitis: often due to the mandibular wisdom teeth obstruction, the performance of the affected side of the posterior tooth area swelling pain and discomfort. The pain increases when chewing, swallowing and opening activities. 9, dry socket: often occurs 3-4 days after tooth extraction, local persistent severe pain, can also be accompanied by general fever and other uncomfortable symptoms. 10, other: another disease that can induce and accompany toothache is osteomyelitis of jaw, acute maxillary sinusitis, malignant tumor of jaw, malignant tumor of gum, inflammation of adjacent tissues such as tooth-containing cyst of jaw, systemic diseases such as: female menstrual toothache, ischemic heart disease, leukemia, hysteria, etc. can be accompanied by toothache. In conclusion, we should recognize the multi-causal nature of toothache and take measures to protect our teeth by combining self oral health care and professional prevention and treatment, so that a healthy and happy life should start from teeth.