婴儿的肠胃很容易受细菌或过滤性病毒感染而引起腹泻。另外有部分婴儿先天性对牛奶的蛋白质敏感或缺乏消化乳糖的功能，在进食婴儿奶粉后会引起腹泻。因上述各种原因而引起的腹泻都会使小肠壁受损伤，令到小肠的细胞丧失消化和吸收的功能。其中制造乳糖酶的细胞最易受破坏而不 Baby’s stomach is susceptible to bacterial or viral infections and causes diarrhea. In addition there are some babies congenital milk protein or lack of lactose digestion function, can cause diarrhea after eating infant formula. Diarrhea caused by these various causes can damage the lining of the small intestine and impair the digestion and absorption of cells in the small intestine. Among them, lactase-producing cells are the most vulnerable to destruction