Abstract: Objective To study the significance and effectiveness of clinical pharmacist's participation in clinical practice. Methods The clinical pharmacists participated in the whole treatment of the patient's acute B-lymphoblastic leukemia combined with the lung infection, by participating in formulating and adjusting the treatment plan of the anti-infectious drugs, monitoring and dealing with the adverse drug reactions, providing pharmaceutical care, playing the role of clinical pharmacists and then promoting the rational drug use. Results Through the participation of the clinical pharmacists, the anti-infection therapeutic regimen for the patient is reasonable and effective. The disposition of adverse drug reaction is rational, and the patient was discharged with the better health. Conclusion The clinical pharmacists should participate in the clinical practice actively, give full play to the medicine knowledge, reflect the value of the clinical pharmacists, and promote the rational medication.

Key words: clinical pharmacist, rational medication, treatment plan, adverse drug reaction