As we all know, early detection and early treatment of lung cancer are crucial to long-term survival. However, since the symptoms of lung cancer in early stage are often not very obvious and there are limitations in the means of early diagnosis, nearly 70% of non-small cell lung cancer patients are already in locally advanced stage or metastasis when they are found; at this time, the conventional treatment means are traditional radiotherapy and chemotherapy, and patients often have to experience unbearable drug toxic side effects, and many patients cannot complete the treatment regimen as a result. The molecular targeted drugs (ERSA, Troche), which are now becoming popular, have submitted a satisfactory answer to crack this problem. Although molecular targeted drugs have only a history of several decades, they have been rapidly used in clinical practice due to their clear efficacy and mild adverse effects, and are known as one of the four major therapies for the treatment of lung cancer, namely surgery, radiation therapy, chemotherapy, and molecular targeted therapy. At present, molecularly targeted drugs are mainly divided into three categories. The first category is epidermal growth factor inhibitors. The commonly used drugs are Troche and Erythropoietin. Their main mechanism is to control the growth of lung cancer by binding to specific targets (epidermal growth factor receptor, EGFR) and initiating the corresponding signaling pathways. The second category is anti-angiogenesis inhibitors, such as Avastin. Its main mechanism is to block the generation of tumor neovascularization, thus making the tumor growth lack sufficient nutrition, and most importantly, to achieve the purpose of starving the tumor. Currently, both of these drugs are widely used in clinical practice and have been established as one of the standard treatment protocols by the American Comprehensive Cancer Treatment Agency. The third category is immune-targeted drugs, which are under clinical research, but have shown better therapeutic effects and less adverse effects. The specific molecular targeting drugs should be applied under the guidance of oncologists, and should not be bought on the internet for application. Because, on the one hand, it is difficult to guarantee the quality of drugs, and more importantly, once the drugs are ineffective, they have certain adverse reactions instead. Special examples are: some patients have a history of interstitial lung disease, but the patients applied targeted drugs without genetic testing, the efficacy is not good and the interstitial lesion is aggravated. Precautions for the application of molecular targeting drugs: 1. As one of the four major therapies, it cannot replace other therapies. Under the guidance of comprehensive treatment concept, oncologists will reasonably arrange the effective combination of different therapies and strive to achieve the best therapeutic effect. On the contrary, patients’ own medication will destroy the wholeness of treatment, which will not only fail to achieve the expected effect, but also affect the implementation of other effective therapies. 2. it is best to clarify the pathological type and genetic background of lung cancer cells before application. the treatment guidelines developed by the American Society of Clinical Oncology in 2014 emphasize molecular guidelines. In most cases, detection of one marker for squamous carcinoma (p63) and one marker for adenocarcinoma [thyroid transcription factor 1 (TTF-1)] is sufficient. For adenocarcinoma, large cell carcinoma, or unclassified NSCLC, ALK testing is recommended for category 1, and testing is not limited to lung adenocarcinoma. Epidermal growth factor receptor (EGFR) ± ALK is recommended for testing as two targets for multiplex or next-generation sequencing in NSCLC, especially in patients with squamous and mixed histologic types who do not smoke or have small specimens. For patients with EGFR mutations and ALK rearrangement negativity, other mutation testing may be considered. As sensitive mutations targeted by tyrosine kinase inhibitors (TKI), testing for the L861 mutation in EGFR exon 21 and the G719 mutation in exon 18 is recommended. Pathological specimens can be obtained from surgical specimens, sputum, pleural fluid, lymph nodes, etc. While the genetic background test mainly uses the tumor specimen method, a new method using peripheral blood detection has been developed by a research unit (Shanghai) in China, and the accuracy is similar to that of tumor specimens, solving the difficulty of collecting tumor specimens from patients. Clinical studies have found that EGFR testing can increase the efficiency of targeted drugs to over 90%, which greatly saves medical costs. The current situation is that ERSA has better efficacy in Asian applications, especially in non-smoking female adenocarcinoma patients, while Trocet tends to be used in male squamous cancer patients. Of course, the specific situation needs to be analyzed in the context of the patient’s specific situation. 3.Pay attention to timely assessment. Improvement of clinical symptoms can usually be shown in one month. Such as cough, coughing blood, chest pain reduction, etc. Two months for chest CT or PET/CT for evaluation. If the effect is not good, stop the drug in time to avoid delaying the disease. 4. Pay attention to the management of adverse reactions. Although the adverse reactions of targeted drugs are very small, there are certain side effects. The common ones are rash, acne, dandruff, dry skin, diarrhea, etc. In addition, interstitial lung changes are of low firing rate but serious consequences, which have been found to require immediate discontinuation of the drug; in addition, more serious diarrhea does not improve after treatment also requires discontinuation of the drug. In addition, some patients have liver dysfunction, so regular review of liver function is required. As for Avastin, since the treatment is required to be applied in hospital, it is more convenient to monitor adverse reactions and will not be repeated. Common adverse reactions: gastrointestinal perforation/wound dehiscence syndrome; bleeding; hypertensive crisis; nephrotic syndrome; congestive heart failure. Treatment is mainly carried out by medical professionals. 5. Drug resistance problems. Primary resistance to targeted drugs TKI is associated with KRAS mutations, and acquired resistance is associated with second site mutations in the EGFR kinase region (e.g., T790M), amplification of other kinases (e.g., MET), histological transformation of NSCLC to small cell lung cancer, and epithelial mesenchymal transition (EMT). Chemotherapy is considered if drug resistance occurs. 6. Chinese medicine treatment for adverse reactions. According to the long-term observation and follow-up of patients applying targeted drugs, I believe that the adverse reactions of targeted drugs should be treated with blood-heat and damp-heat as the main treatment, often combined with spleen deficiency and yin deficiency over time. The treatment adopts the comprehensive treatment of Chinese medicine, and has achieved good effect on the rash and diarrhea and other adverse reactions.