The tooth has a hole which is smelly and painful when sucking down, generally it is considered to be related to tooth decay, it belongs to the cavity formed by the tooth decay caused by food embedment, when the food residue stays in the cavity for a long time, it may cause smelly, the patient can feel the pain of the affected tooth, and the pain is aggravated when sucking. Some people like to eat sweets, drink drinks, etc. Due to the high intake of sugar, under the interaction of bacteria and sugar, it will destroy the tooth enamel and induce tooth decay. Improper brushing or inability to insist on brushing will lead to poor oral hygiene environment, and the massive breeding of bacteria will lead to tooth demineralization and dental caries. If the teeth are not aligned and the dental health is not good, the bacteria will be more likely to invade and the caries will appear over time. In order to treat a hole in the tooth which is smelly and painful to suck down, we need to consider the severity of tooth decay. If the degree of caries is mild and the lesion does not involve the dental nerve temporarily, the patient can use mouthwash or light salt water to rinse the mouth first, try to discharge the residue in the cavity and make the initial cleaning of the mouth, which can help to relieve the discomfort. However, if no clinical intervention is given at this time, the caries may become deeper and deeper, so it is recommended to seek medical attention in time. If the doctor determines that it is initial caries, filling as well as preventive filling can be performed. However, if it is deeper and cannot be repaired by itself, a filling is needed to restore the original shape of the tooth. If the lesion has involved the nerve of the tooth, generally, root canal treatment is needed to kill the nerve and then restoration treatment. In addition, if the caries patient has concurrent pulpitis, periapical infection, gingivitis and other diseases, there will also be a hole in the tooth, very smelly, and painful when sucking, it is recommended to treat the caries at the same time to carry out anti-inflammatory treatment for the complications. If there is local obvious abscess, patients can go to the hospital for incision and drainage treatment, with the exudate discharge, the cavity will be smelly, painful and other symptoms will be relieved.