Stomach upset after bladder perfusion may be an adverse reaction produced by the drug stimulating the stomach and intestines, which is usually a normal phenomenon. Bladder instillation, which utilizes chemotherapeutic drugs to kill bladder cancer cells, is a kind of chemotherapeutic method, which is usually used for postoperative adjuvant treatment of bladder cancer. The risk of tumor recurrence can be reduced by killing and inhibiting bladder tumor cells through bladder instillation of appropriate drugs. Stomach discomfort after bladder instillation may be caused by the drugs stimulating the stomach and intestines, thus causing the body to experience nausea, vomiting, diarrhea, constipation, abdominal distension, abdominal pain and other adverse reactions of the stomach. After the end of bladder perfusion patients should drink more water to increase the amount of urine, which can speed up the residual drug out of the body and prevent urinary tract infection. And eat a reasonable diet, avoid spicy stimulating food, do not drink cola, coffee, wine and other beverages to reduce bladder irritation. It is recommended that patients with stomach discomfort after bladder instillation, if the symptoms are not relieved for a long time, they should go to the hospital in time to avoid delaying the condition and causing adverse consequences.