Repeated mouth ulcers can occur due to stress, lack of sleep, acidity, spicy foods, vitamin deficiencies, low immunity, stomach irritation, hormonal changes, or friction from sharp teeth. Many people describe a feeling of ?body heat? before ulcers appear because irritation and inflammation inside the mouth increase during flare-ups. If ulcers come almost every month, the body may have an ongoing trigger rather than a simple temporary infection. Frequent ulcers are sometimes linked with low vitamin B12, iron, or folic acid levels, especially when there is tiredness, poor diet, or weakness. Sour, spicy, and very hot foods may worsen pain and delay healing. Doctors often use soothing mouth gels, antiseptic mouthwashes, vitamin supplements, and medicines that reduce inflammation to control repeated ulcers and improve comfort. Drinking enough water, improving sleep, reducing stress, and maintaining regular meals may help reduce recurrence in some people. Large ulcers, weight loss, fever, bleeding, or ulcers lasting many weeks should be evaluated thoroughly, as persistent mouth sores may require further evaluation.