Chemotherapy, or chemotherapy for short, is the treatment of tumors with chemical drugs. Chemotherapy is one of the most important treatments for tumors and a key component of comprehensive cancer treatment. Its history can be traced back to the 1940s, and its rapid development in the last two decades. Today, although targeted therapy has become a hot topic of research and discussion, chemotherapy remains the most common and important systemic treatment for tumors. From preoperative neoadjuvant chemotherapy, to postoperative adjuvant chemotherapy, to palliative chemotherapy after metastasis, chemotherapy is used throughout the treatment of most tumors. However, whenever chemotherapy is mentioned, many people first associate it with vomiting until bile is vomited, hair loss until none is left, mental depression, or loss of resistance, and they have a sense of fear about the side effects of chemotherapy. In fact, if you can roughly understand the principles of chemotherapy, the causes of side effects and the principles of prevention and treatment, you may be able to face chemotherapy openly, minimize the side effects and strive for maximum benefits. The main mechanism of action of chemotherapy drugs is to inhibit the synthesis of DNA or RNA of tumor cells, thus killing tumor cells. However, since there is no fundamental difference in metabolism between normal cells and tumor cells, chemotherapeutic drugs kill tumor cells while often have some damaging effects on normal cells, especially those proliferating weaving cells, which are also easily damaged by chemotherapeutic drugs. These proliferating tissue cells include gastrointestinal mucosa, hair follicle cells, white blood cells, etc. The damage to these cells causes the most common side effects we see during chemotherapy, such as nausea and vomiting, hair loss, and decrease in white blood cells. However, the cells of these normal tissues are more likely to recover from the damage of chemotherapy, making the damage of chemotherapy drugs to tumor cells more obvious for the purpose of tumor treatment. In the process of understanding chemotherapy, several misconceptions need to be clarified: 1. As long as chemotherapy is given, side effects such as vomiting and hair loss will inevitably occur. In fact, this view is wrong. Not all chemotherapy patients will have side effects. Each side effect occurs with a certain frequency, but not 100%. The same drug may have one side effect in this patient and not in another, or another side effect. And the same side effect may be mild in some patients and may be more pronounced in others, also varying from person to person. Therefore, do not refuse chemotherapy that you should receive just because someone else has side effects. 2, not all chemotherapy drugs have the same side effects, some may have significant hair loss, some may have significant white blood cell drop, and some may not even have any side effects, the side effects of various drugs are not the same. When formulating chemotherapy regimens, in addition to considering the effectiveness of the treatment, doctors often individualize the choice of different chemotherapy regimens based on different patients’ health conditions and personal wishes regarding side effects. Therefore, if you are a patient, before receiving treatment, you should let your doctor fully understand your physical condition and tell him your acceptance level of different side effects, which will often help your doctor to deal with your side effects in time and complete chemotherapy successfully. 3, many people believe that in order for chemotherapy to work, you must have side effects. This is also a misconception, in fact, there is no correlation between the side effects of chemotherapy and the efficacy of the treatment. Effective chemotherapy regimens may sometimes have insignificant side effects, and chemotherapy that cures patients because of side effects is not a good treatment choice. The ideal chemotherapy regimen should be highly effective and less toxic, with the lowest side effects for the best outcome. With the development of medicine, more and more new drugs are being introduced, and these new drugs often have lower side effects and even better efficacy. Therefore, at present, during chemotherapy, the patient may not lose hair, or vomit, or the white blood cell does not decrease, but the efficacy is more significant, so the chemotherapy is more easily accepted by the patient. Moreover, the side effects of chemotherapy can be prevented or treated, and reasonable treatment methods can reduce the frequency of side effects, reduce the degree of side effects, and shorten the duration of side effects. 4.Many people think that chemotherapy is palliative treatment and cannot achieve the purpose of radical cure. This view is also wrong. Many tumors can be cured by chemotherapy alone, such as testicular tumors and lymphomas; there are also many tumors that need to receive adjuvant chemotherapy after radical surgery in order to further improve the cure rate, such as breast cancer and colorectal cancer. Even for many advanced tumors, which are already incurable, chemotherapy can achieve the purpose of prolonging survival and improving quality of life. Therefore, never ignore the value of chemotherapy and do not give up the choice of chemotherapy easily. With the deepening of research, the development of chemotherapy drugs is also changing day by day. More and more drugs with new mechanisms of action are entering clinical use, and they often have positive efficacy, mild side effects, and many side effects can be prevented and controlled early. Many old chemotherapeutic drugs can also be further improved in efficacy and toxicity by changing dosage forms, excipients, precursor drugs, etc. Therefore, chemotherapy still plays an indispensable role in various tumor treatments. As patients and their families, when they understand the potential benefits of chemotherapy for tumor treatment, they need to fully understand chemotherapy, its mechanism and side effects, and more importantly, learn how to manage chemotherapy well so as to complete it successfully. In this issue, we invited some doctors from our department to answer common chemotherapy questions in clinical practice, hoping to be beneficial to our patients.