Ankylosing spondylitis generally does not cause anemia, anemia may be caused by adverse drug reactions during the treatment of ankylosing spondylitis, or may be caused by autoimmune hemolytic anemia. 1. Ankylosing spondylitis: Ankylosing spondylitis mainly involves the large joints of the limbs, the central axis of the skeleton and the spine, and causes low back pain, morning stiffness and joint swelling and pain, and does not usually cause anemia in patients. 2. Adverse drug reactions: Ankylosing spondylitis treatment is mainly based on drug therapy, commonly used drugs include non-steroidal anti-inflammatory drugs, improve the condition of anti-rheumatic drugs, including leflunomide, methotrexate and salazosulfapyridine to improve the condition of the anti-rheumatic drugs may cause blood system disorders, resulting in anemia. In addition, long-term use of non-steroidal anti-inflammatory drugs may also cause gastrointestinal bleeding, resulting in anemia. 3. Autoimmune hemolytic anemia: autoimmune hemolytic anemia is caused by autoimmune dysfunction resulting in destruction of red blood cells, patients may have anemia, chills, high fever, cyanosis and other symptoms. Anemia may also be caused by other reasons, and it is recommended that patients go to the rheumatology and immunology department, hematology department and other related departments of regular hospitals for further clarification of the cause of the disease.