If you are hungry and dizzy from the bowel cleanse before the colonoscopy, you may be given intravenous fluids to give parenteral nutrition. The day before the patient’s colonoscopy, the physician will request a light, liquid or semi-liquid diet. On the day of the colonoscopy, drugs such as polyethylene glycol electrolyte dispersion are given to induce diarrhea, and the patient stops eating and drinks electrolyte-dispersible water and then strives to empty the intestinal cavity. Some weak patients may not be able to tolerate prolonged hunger and may experience dizziness, weakness, and even hypoglycemic reactions such as cold sweat, black eyes, and panic. This condition requires immediate bed rest, and intravenous fluids should be given after reporting to the doctor to supplement sugar, salt, electrolytes, amino acids, vitamins and other nutrients to enhance extra-intestinal nutritional supplementation. Usually this condition is transient and will be relieved soon after rehydration, and the colonoscopy will be performed after the body functions recover.