Targeted therapy and chemotherapy are both drug treatments for cancer. There are certain differences between the two in terms of treatment principle, therapeutic effect and side effects of treatment: 1. It is also known as biological missile. Chemotherapy, on the other hand, is the application of chemical drugs to target tumor cells that proliferate faster, and through destroying the DNA structure and function of tumor cells, inhibit their growth, replication and division, so that tumor cells lose their growth ability, which is a systemic therapy. If the surface of cancer cells contains such target substance, it can destroy the cancer cells containing the substance. Therefore, compared with chemotherapy, targeted therapy can specifically target tumor cells. While chemotherapy can treat a wide range of tumor lesions and prevent metastasis, there will be certain damage to normal cells. 3. Different side effects: Targeted therapy has significantly lower toxicity to the body, so the side effects of targeted therapy are lower compared with chemotherapy, but still patients may suffer from rash, nausea, diarrhea and other symptoms. Chemotherapy drugs, on the other hand, are special drugs developed according to the cycle of cells and are cytotoxic drugs, which can also have toxic side effects on normal cells in the body, with greater toxic side effects and longer cycles. Patients can occur liver function damage, kidney function damage, digestive system damage, bone marrow suppression and hair loss and other adverse reactions; 4, the applicable population is different: targeted drugs have specific targets for specific driver gene population, targeted drugs generally need to carry out NGS gene sequencing to find a suitable population. While chemotherapy drugs do not have a specific population selection, mainly considering the patient’s tolerance. Targeted drugs are generally more expensive than chemotherapeutic drugs, so patients need to consider their condition, their own economic conditions, personal physical condition and other factors, and choose the appropriate treatment under the guidance of doctors to promote disease recovery.