Dark lines at the gums may be caused by pigmentation, and patients should get into the habit of brushing their teeth. It may also be caused by periodontitis, caries and other diseases, patients can take surgical treatment and other ways to deal with. 1. Hyperpigmentation: If the patient smokes for a long time, it will lead to hyperpigmentation, which will lead to the symptom of black lines at the gums. It is recommended that patients brush their teeth on time in their daily life, after eating or smoking, but be careful to use the correct way of brushing. Regular oral cleaning to avoid plaque pigmentation. 2. Periodontitis: For periodontitis caused by black lines at the gums, patients will also have symptoms such as bleeding from brushing, red and swollen gums. Systemic periodontal treatment can be taken. 3. Caries: Teeth near the gums are decayed, which may also show up as black lines. Filling treatment is needed to remove the decayed tissue. When the patient has the symptom of black lines at the gums, if it is caused by pigmentation, no special treatment is needed. If it is caused by a disease, the patient should seek medical attention in a timely manner and follow the doctor’s instructions for treatment.