In recent years there has been a sharp increase in the number of patients undergoing chemotherapy for tumors. All kinds of chemotherapeutic drugs have toxic effects on the tissues with active growth, and all of them have different degrees of myelosuppression and gastrointestinal reactions. In order to eliminate patients’ concerns, the author summarizes several common problems and prevention methods for reference only. What are side effects? Side effects are the adverse reactions caused by the treatment. Common side effects caused by chemotherapy include fatigue, nausea, vomiting, decreased blood cells, hair loss, mouth ulcers and pain. What causes side effects? Chemotherapy was originally designed to kill cancer cells that proliferate rapidly, but it can also have a damaging effect on normal cells that proliferate faster. Normal cells in the body that proliferate rapidly include the superficial epithelium of the oral cavity and gastrointestinal tract, blood-forming cells in the bone marrow, and hair follicle cells that produce hair. When chemotherapy damages these normal cells, it can cause corresponding side effects. Will chemotherapy have side effects for me? You may experience many side effects, or only some, or none at all. These depend on the type and dose of the chemotherapy drug and the body’s response. Talk to your doctor or nurse about possible side effects before your chemotherapy treatment. How long do the side effects last? The duration of side effects depends mainly on the physical condition and the chemotherapy regimen used. Most side effects disappear after chemotherapy is finished, but sometimes they can last for months or even years before disappearing. Sometimes. Chemotherapy can cause irreversible long-term side effects, which include permanent damage to the heart, lungs, kidneys, reproductive and other organs. Some chemotherapy can cause a second tumor. Ask your doctor about possible long-term side effects. How can I cope with side effects? Your doctor has many ways to prevent and manage the side effects of chemotherapy and will help you eliminate them with each treatment during chemotherapy. You can find out from your doctor and nurse what side effects you may experience and what to do about them. It is important to inform your doctor and nurse of any discomfort or changes in your health, some of which may be signs of side effects.