Irrational drug therapy may appear during the whole therapeutic process and in every step. The irrational medication for asthma primarily manifests in the improper overall arrangement of medication and inappropriate design and implement of therapeutic schedule. Whether rational medication or not should be judged on the basis of the characteristics of the disease, the patient and the drug itself. We need to do our best to find out the irrational drug therapy, and then manage it actively by adjusting the direction and goal of medication, and/or adjusting the schedule and implement of medication. What’s more, we should be aware of the relativity of rational and irrational drug therapy. In the process of managing the irrationality, we must be flexible, and should assess the pros and cons, balance benefits and harms, avoid disadvantages, and then make appropriate decisions finally.