In general, most patients with chronic granulocytic leukemia who take Gleevec effectively can survive for a decade or more on long-term use. Currently, a targeted drug, Gleevec, also known as Imatinib, has been developed for chronic granulocytic leukemia. If a patient with chronic granulocytic leukemia is reviewed after 3 months of taking Gleevec, the indicators are good, proving that Gleevec is effective for chronic granulocytic leukemia. Patients can then take Gleevec for a long time to prolong their survival, with most patients surviving for more than 10 years and a few patients surviving for up to 20 years. In conclusion, the development of Gleevec has not only changed the prognosis of the disease, but has also contributed to advances in methods of monitoring efficacy. In addition, severe water retention can occur in approximately 1-2% of patients taking Gleevec, so patients are advised to monitor their weight regularly and take appropriate supportive therapy if necessary.