After taking magnesium sulfate two hours no reaction normal or not to be specifically analyzed, some people are not sensitive to the reaction of magnesium sulfate, two hours no reaction is also considered normal; and most people in two hours is a reaction, diarrhea, if there is no reaction may be caused by intestinal obstruction and other reasons. After taking magnesium sulfate, magnesium sulfate is not easy to be absorbed by the intestinal tract, stays in the intestinal tract leading to high intestinal osmolality, preventing the absorption of water in the intestinal tract, and playing a diarrhea-inducing role. In general, there can be a significant reaction to the symptoms of diarrhea one hour after taking magnesium sulfate. Some people are not sensitive to magnesium sulfate, two hours after taking no reaction is not abnormal, you can drink some more magnesium sulfate, drink more water, more walking to promote diarrhea. If there is still no response, may be intestinal obstruction caused by intestinal obstruction and other diseases, there will be no intestinal contents downward discharge phenomenon. Special attention should be paid to the magnesium sulfate diarrhea should be carried out under the guidance of a doctor, any discomfort in a timely manner, intestinal bleeding patients, patients with acute abdominal disease, and pregnant women, menstruating women are prohibited to use this drug diarrhea.