Mouth ulcers, if recurrent aphthous ulcers, usually take thalidomide for a few days to a week or so to see the effect. 1. Thalidomide tablets were originally used for the treatment of pregnancy vomiting and anti-leprosy reaction, later found to have immunomodulatory effect, anti-angiogenesis, etc., has been widely used at home and abroad for the treatment of recurrent aphthous ulcers, clinical application in the heavy aphthous ulcers and other stubborn ulcers have a better therapeutic effect. Generally take thalidomide several days to a week or so can see the effect. 2. However, it should be noted that the serious side effects of the drug is teratogenic (“seal babies”), so patients with oral ulcers in the reproductive period should be cautious, pregnant women are prohibited. Other side effects include peripheral neuritis, constipation, dizziness, drowsiness and nausea. All of the above medications should be used under the guidance of a doctor, avoid self-medication.