The cause of diarrhea from consuming milk is not caused by the cold nature of milk or drinking it cold. Milk contains lactose, and some people have diarrhea caused by drinking milk because of the lack of lactase, which causes malabsorption of sugar in the small intestine, and the sugar molecules cannot be digested or absorbed and exist in the intestinal cavity, causing diarrhea due to the increase in osmotic pressure in the intestinal cavity, i.e. lactose intolerance. The lactic acid bacteria in yogurt will digest lactose, so people who have diarrhea from drinking milk should have no problem drinking yogurt. Many people have diarrhea from eating fruits, and it is not because the fruits are cold or eaten on an empty stomach, but because of the lack of fructose carriers in the human body or the poor efficiency of fructose carriers in transferring fructose. The human body can absorb 25-50g of fructose at a time, and 25g of fructose is equivalent to about 8 taels of apples. People with diarrhea can absorb less than 25g of fructose at a time, and the remaining fructose raises the osmotic pressure in the intestinal lumen, causing diarrhea to occur. Therefore, it is called fructose malabsorption, also known as dietary fructose intolerance.