The daily water intake of chemotherapy patients should be decided according to different situations, but the general principle is that the total intake, including the daily intravenous infusion, should be at least 2000mL. The main reasons for chemotherapy patients to drink a lot of water every day are as follows: 1) A large number of tumor cells are necrotic and a large amount of toxic contents are released after chemotherapy, which need to be discharged out of the body along with the water, or else it will lead to the lysis syndrome, and the severe cases will lead to death. 2) Some drugs, such as cisplatin, are highly toxic to the kidney, which requires a large water intake to prevent kidney damage. Some drugs, such as cisplatin, are very toxic to kidneys, which require high water intake to prevent kidney damage. For patients who have received chemotherapy for the first time, due to the large tumor load in the body, i.e., the number of tumor cells is very large, and there is a high possibility of tumor lysis syndrome after chemotherapy, therefore, it is required to have a large amount of water intake, but the amount of intravenous fluids is limited, so it is necessary for the patients to drink 3,000-4,000 mL of water per day. After several times of chemotherapy, the number of tumor cells is obviously reduced, and the amount of water intake can be reduced to about 2000mL, if the chemotherapy drug contains cisplatin, the amount of water intake is also required to reach about 3000mL per day, in short, chemotherapy patients have to drink more water during the period of chemotherapy, which can reduce the incidence of a lot of side effects.