I don’t know if you’ve ever had the experience of brushing your teeth or biting into a hard food like an apple and finding your gums bleeding, or worse, waking up in the morning to find a bloody saliva stain on your pillowcase. However, there is no pain in the mouth and nothing seems to be wrong with the teeth. What is going on here? Some people find that their gums bleed when they brush their teeth or that blood remains on their food when they bite into something hard, which often creates a heavy burden of thought and fear of incurable diseases. In fact, bleeding from brushing is a very common phenomenon, mostly due to gingivitis. Generally speaking, bleeding gums are the external manifestation of systemic or local diseases, of which oral diseases are the most common. Gum bleeding is a typical manifestation of gingivitis and periodontitis. Common causative factors include calculus, food impaction, poor prosthesis (i.e., ill-fitting dentures), incorrect brushing, hormonal secretion changes during puberty or pregnancy, altered immune function, bacteria, and genetics. Among them, dental calculus is one of the most common factors. Under the stimulation of these factors, normal gums become red and swollen, less resilient and prone to bleeding. In addition, some systemic diseases can also cause bleeding gums, such as leukemia and AIDS, which can manifest as bleeding gums, even if oral symptoms appear before systemic symptoms. Other conditions such as thrombocytopenia are also associated with spontaneous gum bleeding and bruising. To solve the problem of bleeding gums, we should first identify the culprit of the bleeding and then treat the symptoms, such as improving the problem of food ingrowth, removing bad restorations, correcting brushing methods, regulating immune function and hormone levels, removing pathogenic flora, etc. For the most common irritant, calculus, periodontal scaling is usually used to remove it. Bleeding gums caused by systemic diseases should be diagnosed as early as possible to facilitate the development of a targeted treatment plan. We know that the presence of plaque, tartar, soft tartar and other undesirable irritants on the dental surface can irritate the gums and cause gingival inflammation if not removed in a timely manner. As the epithelium of the gingival sulcus breaks down when the gums are inflamed, the submucosa connective tissue capillaries proliferate, expand, become congested, the tissue is edematous and infiltrated with inflammatory cells, so clinical examination of the gums reveals that the color of the gums changes from normal light pink to dark red, the appearance is swollen, the texture is soft and fragile, and bleeding occurs when the probe is lightly touched. This is manifested as bleeding gums when brushing or biting on hard objects as mentioned earlier. In addition, hypertrophic gingivitis, gingivitis during pregnancy, and all kinds of periodontitis can also have bleeding gums when brushing. Therefore, there is no need to be alarmed when you find bleeding from brushing your teeth, but you should go to the hospital for systematic examination and, if necessary, routine blood tests to confirm the diagnosis.