Mouth ulcers before and after menstruation may be related to hormonal changes in the body, dietary habits, the body’s resistance to decline and other factors. 1. Hormonal changes in the body, before and after menstruation due to hormonal changes in the body, endocrine disorders, may lead to mouth ulcers. 2. Dietary habits, before and after menstruation, if you do not pay attention to personal diet, often eat spicy greasy stimulating food, may induce mouth ulcers. 3. Decrease in body resistance, before and after menstruation, women’s body resistance decreases, unable to resist the invasion of foreign pathogens, may induce mouth ulcers. If the mouth ulcers appear repeatedly for a long time, you need to pay attention to it, and actively seek medical examination and treatment.