Mouth ulcers are a common and frequent symptom, sometimes related to diet, sometimes related to physical condition, and varying in severity. Patients are often left to their own devices, and not many go to the hospital. If you know that mouth ulcers are a manifestation of rheumatism, you may not take it lightly. The most common clinical diseases with mouth ulcers are systemic lupus erythematosus and leukoarthritis. Systemic lupus erythematosus is an autoimmune disease that occurs more often in women of childbearing age when there is no obvious cause for the appearance of oral ulcers (no obvious pain if there is no infection); or with prolonged fever; or with multi-joint pain, or with facial erythema, or with hair loss, or with photosensitivity (facial erythema does not fade easily after sunlight exposure), or with Raynaud’s disease such as whitening, purple, or redness of the hands and feet when they are cold. The symptoms of Raynaud’s disease include white, purple and red hands and feet after exposure to cold, frostbite like attacks on the face, hands and feet, and ineffective treatment for frostbite, anemia, leukopenia, petechiae or petechiae, etc., proteinuria, increased foam in the urine, or pleural effusion or pericardial effusion, such as chest tightness and shortness of breath after activity. Leukoaraiosis is also an autoimmune disease with a better prognosis than SLE. When there are unexplained oral ulcers (recurrent, self-healing), along with nodular erythema of the skin (mostly on the extremities, slightly above the skin, red and painful when fresh), vulvar ulcers, recurrent eye inflammation such as uveitis, retinal vasculitis, conjunctivitis, iridocyclitis, etc., arthritis, pinprick reaction (redness, swelling and even pus spots at the site of injection or blood sampling), limb motility In the case of phlebitis, headache, hemiplegia, aphasia, etc., prompt consultation should be sought for timely treatment.