Recurrent oral ulcers (recurrent thrush) are the most common oral mucosal disease, with an incidence of up to 25% in the general population and up to 50% in specific populations. Because recurrent ulcers, congestion and pain are obvious and often affect the patient’s speech, eating, work and even mood, thus significantly reducing the patient’s quality of life, the need for treatment or even eradication of the disease is very urgent. To date, the cause of the disease is still unclear, and most scholars believe that it is caused by a combination of immune factors, genetic factors, vitamin and trace element deficiencies, systemic diseases, and mental stress. Since the cause of the disease is so complex, it is difficult to find a specific treatment that accurately addresses the cause of the disease, so there is no once-and-for-all cure. The purpose of treating recurrent mouth ulcers is not to prevent them from recurring, but to reduce the frequency of attacks, alleviate the severity of ulcer attacks, promote ulcer healing, and reduce pain through a series of treatments. The main clinical treatment is with drugs, often including immunomodulatory drugs, vitamins, Chinese medicines, and local drugs. By looking for the possible causes of recurrent mouth ulcers, we try to individualize the medication according to different conditions. Through a period of medication, most patients can get different degrees of improvement. In addition, attention should be paid to the removal of possible local irritants, such as sharp cusp edges, residual roots, residual crowns, and dental calculus.