 Asthma is a heterogeneous disease, which pathophysiology is still poorly understood. Asthma was traditionally divided into allergic, extrinsic and non-allergic, intrinsic types, while patients with allergic type responded better to corticosteroids. Since 2013 the definition of asthma has changed. Recently, better insight into clinical considerations and underlying inflammatory phenotypes has been gained. Defining these phenotypes has already led to more specific clinical trials and, therefore, to more personalized and successfully targeted therapy. For future, much more effort is put in identifying new phenotype-specific biomarkers which could be helpful in stratification of heterogeneous patients with asthma. This article was authored by Palova R., Adam Kakova J., Mokra D., and others.