Bleeding gums while brushing teeth may be caused by incorrect brushing methods that cause gum damage, or the development of periodontal disease that causes bleeding gums. 1. Gum damage. Incorrect brushing, brush bristles overly hard to stimulate the gums, causing gum damage bleeding, so you need to use the right way to brush, do not use brute force brushing, you can use the Bachmann brushing method, brush bristles and teeth neck direction of 45 degrees, to the jaw whisking brush. 2. Periodontal disease. Gingivitis or periodontitis, due to the presence of inflammation, gingival connective tissue capillary expansion congestion, resulting in poor epithelial protection, small stimuli can cause capillary rupture and bleeding, the need for timely removal of external stimuli for periodontal cleaning. Bleeding gums when brushing teeth may also be coagulation dysfunction caused by the gums have a tendency to bleed, specific need to go to the hospital for examination.