One of them was a 48-year-old female patient who came to my specialist clinic for ”left tongue ulcer that did not heal for 3 weeks” by a patient friend. During the consultation, I found that the patient had a left mandibular first molar stump with sharp margins and a one-dollar coin-sized ulcer surface on the left tongue margin, with a cauliflower-like surface and a hard ulcer base. The other patient was a 61-year-old male patient with recurrent painful left buccal ulcer for more than a month, who was diagnosed as medium to high differentiated squamous cell carcinoma and was discharged after surgery and radiation treatment. If the ulcer had been diagnosed and the cause removed in time, the ulcer would not have become cancerous at all. Here is a reminder: for ulcers that do not heal for a long time and recur in the same area, we must be alert to the possibility of ulcer cancer and need to come to the hospital for timely consultation.