Having cancer or some treatments can weaken the immune system, which can lead to vulnerability to bacterial and viral infections, especially chemotherapy, which tends to reduce the number of white blood cells, whose primary function is to fight infection. Factors that can weaken the immune system of cancer patients include: chemotherapy radiation therapy lack of sleep poor nutrition cancer that affects the blood or lymph nodes, such as leukemia or lymphoma cancer that has spread to other parts of the body Precautions to prevent infection in cancer patients: Hand washing. Wash your hands frequently with hand sanitizer, including before meals, after bowel movements, after sneezing, coughing or washing your nose, and even before touching your eyes and nose. Carry an alcohol-based hand sanitizer with you in case you are unable to wash your hands effectively with it when you are out and about. Eat a clean diet. Eat plenty of fresh fruits and vegetables, avoid unclean food (including spicy hotpot, street stalls, barbecue, etc.), don’t buy cooked food directly, don’t try free food tasting, and don’t buy pre-cut fruits and vegetables. Stay away from the source of infection. If someone in your neighborhood has a fever, cold, flu or any other infection, stay away from them until they recover. It is best to avoid crowded places. If you do have to go out in public, use clean wipes to isolate yourself before touching door handles, elevator buttons, ATM keypads, or places where many people have touched them. Take care to protect yourself. Bathe regularly, paying special attention to areas that are prone to sweating or infection. If your skin is dry, it is recommended to use lotion to prevent dryness and cracking to prevent infection. You can use an electric razor instead of a razor to avoid cutting yourself. Use a soft toothbrush and you can use mouthwash appropriately. Personal hygiene. Do not share glasses, utensils or food with other people, and do not use shared towels, toothbrushes or cosmetics.