The author considers a role of interleukin-6 (IL-6) as a cytokine, elevated concentrations of which in serum and synovial fluid correlate with the activity of articular inflammation and the development of systemic manifestations in rheumatoid arthritis (RA). There is strong evidence suggesting that effective treatment with gene-engineering biologicals causes a reduction in IL-6 concentrations. Detailed information is given on the novel drug tocilizumab that is humanized monoclonal antibodies (IgG) and the first and only agent that is able to suppress IL-6-dependent inflammatory reactions and is permitted for use in RA.