Erythroxa, also known as gefitinib tablets, does not have a maximum of a few years can be taken, clinical often according to the patient’s condition of the use of drugs, in line with the indications and does not appear to be resistant to the drug, you can take long-term medication, or else you need to replace the other drugs for treatment. Gefitinib tablets are indicated for the treatment of patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) gene mutation. There is no maximum number of years, usually patients will develop resistance to gefitinib tablets after 6 to 8 months of taking the drug, but there are also patients who take the drug for 1 to 2 years before becoming resistant to the drug. Even if the tumor is well controlled and no drug resistance occurs, the use of the process needs to go to the hospital for follow-up, and the doctor will adjust the dosage of the drug according to the changes in the condition. Common adverse reactions to gefitinib tablets include diarrhea, skin reactions, rash, acne, and itching. It is contraindicated for those who are allergic to the active substance. Patients with dyspnea with cough and respiratory discomfort, elevated liver transaminases, severe diarrhea, nausea should be prohibited from using the drug, and breastfeeding women need to stop breastfeeding during breastfeeding. Gefitinib tablets should be taken under the formal guidance of a doctor and according to their own situation.