Blood blisters in the mouth are commonly associated with mouth ulcers. Oral ulcers, also known as “mouth sores,” are blood blisters that occur on the oral mucosa and can range in size from rice to soybean, round or ovoid, with the ulcerated surface being a concave mouth ulcer, surrounded by congestion, and can be painful due to irritating foods, and can generally heal on their own in one to two weeks. The prevalence in the population is generally considered to be more than 10% and can occur in both sexes, with young and middle-aged people being the most common. Recurrent oral ulcers are a limited ulcerative injury of the oral mucosa characterized by periodic recurrent episodes that can heal spontaneously and can occur in any part of the oral mucosa. The etiology of oral blood blisters is as follows: 1, digestive system diseases and functional disorders: such as bloating, diarrhea or constipation and other conditions. 2, endocrine changes: some female patients tend to occur during menstruation, which may be related to the decrease in the amount of estrogen in the body. Some women develop mouth ulcers around the time of their periods or menstruation, which can only be temporarily relieved by medication and still appear as usual in the next month when they are menstruating, with unbearable pain, and at the same time, are often accompanied by troublesome symptoms such as dry mouth, irritability, irritability and dry stools. Clinical research has found that the appearance of mouth ulcers during menstruation is mainly due to the increase in the level of progesterone and the decrease in the level of estrogen (progesterone, etc.) in the body. 3, mental factors: some patients develop under mental tension, mood swings and poor sleep conditions, which may be related to plant nerve dysfunction.