Janus protein tyrosine kinase (JAK) inhibitors are new therapeutic targets in the treatment of rheumatoid arthritis. Tofacitinib has shown good clinical efficacy in phase II and III studies with American College of Rheumatology (ACR) 20 response rates over 50% for monotherapy and in combination with methotrexate (MTX). Also the safety profile shows similar infection rates as observed with known biologicals. The crude rate of serious infection events was 3/100 patient-years. Often reported adverse events are infections of the upper respiratory tract and urogenital infections.