There are many causes of oral mucosal blisters, including trauma and herpetic diseases. The most common cause of oral blood blisters is local trauma, eating hard objects scrape the palatal mucosa, appearing traumatic blood blisters, often large, 2~3cm in size. The pain is not obvious and there is a foreign body sensation. Mucosal blisters may also be formed if the mucosa is inadvertently bitten by chewing, often located in the corners of the mouth or the buccal mucosa, and are small, 0.5 cm in size. Generally, large blood blisters need to be seen in the mucosa department of a dental hospital or the stomatology department of a general hospital, where a sterile syringe is used to extract the blood from the blister, or the wall of the blister is punctured to release the bruised blood, and topical medication is applied to promote the healing of the ulcer. Oral blood blisters may also be herpetic diseases, the most common of which is mucosal aspergillosis, often appearing on the gingival mucosa, most of which are blood blisters, some of which are bright blisters, requiring consultation at the mucosal department of a dental hospital. For specific medication, please refer to the doctor’s instructions in the clinical setting.