Summary: Biological treatment of asthma began in 2003, when the FDA (Food and Drug Administration) registered the first drug in the United States – an anti-IgE antibody (omalizumab) for the treatment of severe allergic asthma. Since then, four more biologicals have been registered, three belonging to the anti- IL-5 group (mepolizumab, reslizumab and benralizumab) and an IL-4 and IL-13 blocker (dupilumab). Therefore, many years of experience allow us to summarize the pros and cons of biological therapy for severe asthma and attempt to answer many questions: Has this treatment, and to what extent, met hopes for its efficacy and safety? To what extent has it provided better understanding of the pathomechanism of asthma and allergic diseases? How have biologics opened the way to the treatment of other diseases? On the other hand, we already know a lot about problems related to biological treatment, such as the high costs of this therapy or difficulties in qualifying patients for treatment. Increasingly, we also have to make clinical decisions based solely on our own experience, due to the availability of new biologics, because there are no randomized studies that would be helpful in more difficult clinical situations.