Recurrent oral ulcer (ROU) is a self-limiting ulcerative damage of the oral mucosa with periodic recurrence. The etiology is complex and may be related to immunity, genetics, digestive system diseases, micronutrient deficiency and psychological factors. The treatment of ROU includes both local and systemic aspects: local application of nourishing yin and muscle powder, watermelon cream spray, or the use of anti-inflammatory film (mouth sore film), patches (easy to paste), tablets, ointments and gargles; systemic treatment should be carried out under the guidance of physicians, and corticosteroids, immunomodulators (levamisole, Schizophrenia, etc.), reactive stop, vitamins and microelement preparations (multivitamins) should be used according to the patient’s different conditions. The systemic treatment should be guided by physicians, and depending on the patient’s condition, corticosteroids, immunomodulators (levamisole, Schicom, etc.), reactive stop, vitamins and trace element preparations (vitamin B complex, Schilkhorn or Suncun tablets, zinc) should be used, and if necessary, Chinese medicine should be used to treat the symptoms. At present, the technology in China and abroad cannot completely prevent recurrence, but by treating the possible triggering factors, the number of ulcers and the frequency of recurrence can be significantly reduced in most cases and the course of treatment can be shortened.