Tongue ulcers can be caused by various factors, including injuries to the mouth, such as biting the tongue, injuries from dental work, braces or retainers, poorly fitting dentures, burns from eating hot foods, eating acidic or spicy foods, brushing the teeth with a hard-bristled brush, and hormonal changes. Other potential triggers include high stress levels, food allergies or intolerances, certain medications, and some medical conditions. Tongue ulcers are usually not a cause for concern and can be managed at home without seeing a healthcare provider. However, if a person has several ulcers on the tongue or elsewhere in the mouth, or if a mouth ulcer wont heal, it is important to talk to a healthcare provider, as it could be a sign of an underlying health condition, such as mouth cancer.