EPO and asthma: This study investigates the impact of asthma controller medications on erythropoietic response by evaluating serum EPO levels and reticulocyte counts among asthma patients at Murtala Muhammad Specialist Hospital, Kano.<h4>Methodology</h4>This study is a comparative cross-sectional study involving 180 participants, comprising 60 asthmatics on controller medications, 60 treatment-naive patients with asthma, and 60 apparently healthy controls.