Blood when gargling in the morning is caused by bleeding gums. Basically, it is due to more plaque, calculus, poor oral hygiene, calculus long-term pressure on the gum tissue, resulting in the occurrence of gingivitis, resulting in redness, swelling, bleeding and pain in the gum tissue. In this case, it is recommended to consult the hospital in time for a full mouth cleaning to remove plaque, food debris, calculus and other local adverse stimuli, and apply iodized glycerin or minocycline hydrochloride locally in the periodontal pockets to eliminate the inflammation of the gums. If treatment is not carried out in time, the lesions will develop further, leading to the occurrence of periodontitis, and ultimately resulting in alveolar bone resorption, gum recession, loose teeth, which can not be retained. Therefore, it is important to visit the hospital in time for a full mouth cleaning.