Diet before colonoscopy is very important because it is related to whether the colonoscope can be prepared clean, and cleanliness will ensure the accuracy of the examination. Therefore, it is recommended that patients should eat an easily digestible diet, such as eating some soft rice, thin rice, noodles, tofu, eggs, milk and so on, three days before the colonoscopy. It is not recommended that patients eat foods containing coarse cellulose, such as large leafy greens, cabbage, and some high-fiber fruits, such as bananas, and some fruits with seeds, such as kiwi, which can interfere with the preparation of the patient’s intestines. At dinner the night before the patient’s examination, the patient is instructed to make sure to have a semi-liquid, less crumbly diet, drinking only thin rice and not eating vegetables or fruits, especially fruits with seeds, etc. Only with proper intestinal preparation can the cleanliness of the intestinal preparation for the examination be ensured.