Tocilizumab is a humanized anti-IL-6 receptor monoclonal antibody, which binds to circulating soluble IL-6 receptor and membrane-expressed IL-6 receptor, inhibiting IL-6 binding to both forms of IL-6 receptor. Several Phase III clinical trials demonstrate the clinical efficacy of tocilizumab as monotherapy or with disease-modifying anti-rheumatic drugs for adult patients with moderately to severely active rheumatoid arthritis. Tocilizumab in combination with methotrexate after 24 weeks of treatment could induce disease remission in 30% of patients with rheumatoid arthritis refractory to anti-TNF antagonist therapy. The most common adverse reactions reported in clinical studies are upper respiratory tract infection, nasopharyngitis, headache, hypertension and mild, reversible increases in alanine aminotransferase enzymes. Serious adverse reactions include infections, gastrointestinal perforations and hypersensitivity reactions, including anaphylaxis. The clinical efficacy and safety of tocilizumab has led to the approval of this innovative drug for the treatment of rheumatoid arthritis in more than 70 countries worldwide.