Throat ulcers may be caused by reduced body resistance, herpes isthmus, or cancer. 1. Reduced resistance: If you suffer from leukemia, etc., which can lead to a decrease in systemic resistance type of disease, there may be throat ulcers, manifested in the case of long throat ulcers. 2. Herpetic isthmus: if the throat grows ulcers, the location of the ulcers is in the anterior and posterior palate, the posterior wall of the pharynx or the soft palate and other related parts, it may be herpetic isthmus, and most of the reasons for its occurrence are viral infections, such as herpes simplex virus infections, which will appear as throat ulcers. 3. Cancer: If the throat ulcer is malignant ulcer, such as the long-term bad ulcer of tonsil, tonsil cancer is not excluded. In addition, if the parts of pear-shaped fossa and pharyngeal surface are in the state of ulceration and erosion for a long time, the possibility of localized cancer can not be excluded. In case of throat ulcers, it is recommended to observe closely, consult doctor in time when abnormal situation occurs, and carry out symptomatic intervention according to doctor’s instruction.