For heavy aphthous ulcers with a history of recurrent oral ulcers and deep oral ulcers, secondary infections on the ulcer surface should be prevented; for traumatic ulcers, the traumatic factors (e.g. stimulation by residual roots and crowns, bad prostheses) should be removed; for tuberculous ulcers, systemic anti-tuberculosis treatment should be provided; for oral ulcers without the above-mentioned causes or ulcers that do not shrink even after removing the causative factors, the occurrence of oral cancer should be alerted, and biopsy should be performed as soon as possible for clear diagnosis and timely treatment.