The primary goal in the treatment of rheumatoid arthritis (RA) is to maintain 
good quality of life by preventing joint destruction and avoiding disability. 
For this purpose, all patients with the diagnosis of RA should be treated by 
disease-modifying antirheumatic drugs (DMARDs) including biologic DMARDs and 
non-biologic DMARDs. All DMARDs are expected to prevent the progression of bone 
and cartilage destruction of RA patients from the results of in vitro research, 
and prevention of joint destruction is confirmed in vivo in all biologic DMARDs, 
but not in all non-biologic DMARDs. In this chapter, we would like to review the 
results of basic researches and clinical studies to demonstrate the prevention 
of joint destruction by non-biologic DMARDs that have been frequently used I 
daily practice.