Tongue ulcers may be caused by immune deficiency, nutritional imbalance, inflammation and trauma. 1. Decreased immunity: When the body’s immune system is abnormal, such as a cold, it may activate latent viruses in the body, which can cause tongue ulcers. 2. Nutritional imbalance: Usually, it may be caused by the patient’s lack of vitamin B, vitamin C or trace elements such as iron and zinc as well as endocrine disorders. 3. Inflammation and trauma: Usually patients have long-term oral trauma and acute inflammation, such as stumps and crowns, which usually irritate the tongue and cause ulcers. Or the patient may smoke and drink alcohol regularly, which may also lead to tongue ulcers. There may be many other causes of tongue ulcers, and patients are advised to actively seek medical attention and undergo relevant examinations and treatments under the guidance of a medical professional.