Teeth will bleed when sucking, may be the existence of gingivitis, periodontitis and other diseases, inflammation repeated stimulation and thus cause teeth bleeding. 1. Gingivitis: Due to the repeated stimulation of inflammation caused by the accumulation of plaque at the gingiva-dentine bond, the periodontal capillaries are damaged when suction is performed, and the teeth will bleed when suction is performed. 2. Periodontitis: due to plaque, food impaction, calculus and other factors lead to periodontitis, inflammation repeated stimulation, periodontal mucosa congestion and edema, can appear teeth will bleed when suction performance. When the teeth will bleed when sucked, should go to the hospital in time, clear the cause of the disease, active treatment, to avoid the further progress of the disease.