Oral ulcers are a common and frequently occurring disease, with many causes. A lack of trace elements, such as zinc, is also a factor in their development. In addition to this, the causes of oral ulcers include genetic factors, immune factors, infectious factors, and deficiencies in nutrients such as vitamin B2 and iron among other trace elements, all of which can lead to the occurrence of oral ulcers. Apart from comprehensive treatment, it is important to pay close attention to our diet regularly, supplementing vitamins and trace elements, for instance by eating more fruits and vegetables, and increasing intake of eggs and lean meat to replenish trace elements, thus preventing the recurrence of oral ulcers.