After scaling, the gums still bleed because of the recurrence of periodontitis or plaque and tartar residue, as follows. 1. Recurrence of periodontitis: after scaling, if oral hygiene is not well maintained, plaque and tartar are deposited in periodontal tissues again, which will lead to recurrence of periodontitis, and the symptoms of bleeding gums will appear again. 2. Residual plaque and tartar: dental scaling may not be able to remove all the plaque and tartar, there may be residual plaque and tartar in deep periodontal pockets and root bifurcation, and the residual plaque and tartar will cause inflammation, resulting in bleeding gums. After scaling or bleeding gums may have other reasons, it is recommended to go to the hospital in a timely manner, with the help of the doctor to clarify the reasons for targeted treatment.