The therapeutic arsenal available today for the treatment of asthma, based on the use of corticosteroids combined with long-acting beta agonists, also includes leukotriene modifier, theophyllines, long-acting muscarinic agents, macrolide antibiotics, vitamin D, allergen immunotherapy, aspirin desensitization, dihydrofolate reductase inhibitor, hormones, CRTh2 antagonist, and monoclonal antibodies (mAbs), such as anti-IgE, anti-IL-4R, anti-IL-5, anti-IL-1R, anti-IL-13, anti-IL-17, anti-IL-25, anti-IL-33, and anti-TSLP [5]. This evidence concerns the gene DHFR and asthma.