Cold light teeth whitening is a commonly used treatment to whiten teeth, and formal injuries usually do not cause serious harm. However, some people may experience tooth decalcification, tooth hypersensitivity, and soft tissue damage after doing cold light whitening. Cold light whitening is a medical treatment for teeth whitening, which can effectively whiten teeth, but some patients may experience the following side effects: (1) Decalcification of teeth: As the teeth are whitened by cold light whitening, decalcification may occur on the surface of the teeth, but it can be generally recovered by itself, and the calcium deposition of saliva will make the teeth recover gradually. (2) Tooth allergy: during the process of cold light teeth whitening, the whitening agent will stimulate the pulp cells, so that some patients have the symptom of tooth soreness, but usually can subside by itself. If the patient has problems such as wedge-shaped defects and fissured teeth, the symptoms may be aggravated. (3) Soft tissue damage: In the process of cold light teeth whitening, if the whitening agent stays on the gums or soft tissues for a long time, it will cause some damage to the corresponding soft tissues, but it can usually be relieved by itself. Patients who have the above symptoms after cold light teeth whitening are advised to go to the hospital in time for treatment under the guidance of the doctor.