Magnesium sulfate is the method of catheterization for intestinal preparation before doing colonoscopy. Choose 50-100g of magnesium sulfate and take it with boiling water, the amount of boiling water for brewing is 500-800ml, it is recommended to take 500-800ml of brewing magnesium sulfate within 1-2 hours. Do not take too fast, take too fast may lead to nausea, vomiting symptoms. It is recommended to start taking it at 4 or 5 o’clock in the morning, and take 3-2 sips in 20 minutes to half an hour, and stop taking it when the stool becomes clear. Most of the bowel preparation, you need to pay attention to the observation of bloating, do not lead to the aggravation of abdominal pain, so magnesium sulfate is commonly used to check the colonoscopy a method.