2Development of janus kinase inhibitors (JAKi), has significantly modified treatment of various dermatological conditions by targeting essential pathogenesis of inflammatory and autoimmune diseases. Despite therapeutic potentials of these drugs, concerns about safety appeared soon postmarketing consumption. Therefore implementing strong studies to evaluate their safety and efficacy became mandatory. Many studies have been done up to now focusing on JAKi’s serious or acceptable side effects, however, they are often retrospective or have short follow up. Due to importance of JAKi’s role in the treatment of many skin diseases, we decided to present a review on the main points of recent studies, particularly systematic reviews and clinical trials regarding serious side effects.