If a patient is suffering from dental caries that have already caused bad breath, the situation requires active treatment targeting the dental caries. Due to the ease with which food residue and bacteria can accumulate in cavities, this will cause an odor in the mouth. Initially, it is essential to clear out food debris, bacteria, and any decayed material from the cavity. If the cavity is shallow, it can be directly filled with light-cured resin material. After the cavity is filled, the patient's bad breath symptoms should be alleviated. However, if the cavity is deep, it should first be treated with a pulp-protecting base before filling. If the dental nerve is affected, causing pulpitis, root canal treatment must be conducted first.