The side effects that can occur with Mesalazine Extended-Release Tablets include allergic reactions, cardiovascular system symptoms, neurological symptoms, gastrointestinal system symptoms, hematologic symptoms, and urinary system symptoms. 1. Allergic reactions: such as skin rash, bronchospasm, drug fever, etc., the occurrence of which is usually not related to the drug dose. 2. Nervous system symptoms: such as headache, dizziness, decreased concentration, memory loss, disorientation and so on. 3. Cardiovascular system symptoms: as the drug may affect the normal heart muscle, thus making the patient appear electrocardiogram changes, chest pain and so on. 4. Digestive system symptoms: such as nausea, vomiting, constipation, diarrhea, dry mouth, etc. A few patients may experience changes in the parameters of liver function in the body (elevated transaminases). 5. Joint and muscle symptoms: such as spasmodic muscle pain, arthritis, joint pain and so on. 6. Hematologic symptoms: dysplastic anemia, granulocyte deficiency, pancytopenia, neutropenia, leukopenia and thrombocytopenia may occur. 7. Urinary system symptoms: renal dysfunction may occur, including acute and chronic interstitial nephritis and abnormal renal function. Drugs should be used under the guidance of a doctor, if adverse reactions need to consult a doctor.