Ms. Zhao has a difficult problem to talk about, the mouth will float out of the odor when talking, brush teeth always gum bleeding, eat apples often leave a few blood marks on the apple, from time to time, the gums also swell and pain for a while, so she is quite annoyed. The doctor clearly diagnosed it as periodontitis. Over the years, she went from hospital to hospital, took many drugs and received various treatments, but her gum bleeding symptoms still recurred. Finally, she gave up treatment altogether. Two years ago, she received hyperbaric oxygen treatment for recurrent dizziness. After 5 treatments, she unexpectedly found that her gum bleeding symptoms improved significantly, and after 10 treatments, the symptoms disappeared completely. With that, her breath was refreshed and the swollen and painful gums disappeared. She is even happier that her gum bleeding symptoms have not recurred since. Chronic gum bleeding is a common symptom of oral disease, which occurs when brushing teeth and biting hard objects, often accompanied by swollen and painful gums. These symptoms are mostly seen in patients with chronic gingivitis and periodontitis. The prevalence of chronic gingivitis in China is as high as 70-90%, mainly seen in children and adolescents. The prevalence of periodontitis increases with age, with a high incidence after the age of 35. Chronic gum bleeding is recurrent and difficult to cure, and all types of invasive treatment add to the patient’s pain. Hyperbaric oxygen therapy is the inhalation of pure oxygen at a pressure higher than one atmosphere for the purpose of treating the disease. The current commonly used treatment pressure is two atmospheres. It has such a miraculous effect on chronic gum bleeding mainly because: hyperbaric oxygen therapy can inhibit the growth of certain bacteria within the plaque; it can improve gingival microcirculation, resulting in increased gingival oxygen content, faster blood flow, and promoting microangiogenesis; hyperbaric oxygen therapy has an immunomodulatory effect, thus inhibiting gingival inflammation and alveolar bone resorption; it can also promote gingival tissue repair. As a non-invasive and less painful treatment method, hyperbaric oxygen therapy is one of the treatments worthy of attention and choice for patients with chronic gum bleeding. Periodontal basic treatment combined with hyperbaric oxygen therapy is effective in treating periodontal disease.