A 1-month-old baby with yellow, thin stools may have indigestion or viral enteritis, and a stool test is recommended to clarify. Under normal circumstances, breast-fed babies have yellow or golden-yellow stools, uniformly paste-like, or with a little yellow stool particles, occasionally slightly dilute and slightly green, not smelly, with a sour taste, 2-4 times a day. If the baby is artificially fed, the stool should be light yellow and grayish yellow, dry and thick, with a foul odor, and 1-2 times a day. If the stool smells bad, it means protein indigestion; if it smells sour and foamy, it means carbohydrate indigestion; if the appearance is creamy, it means fat indigestion; milk flap in the stool is mostly soap lump of undigested fat and calcium or magnesium, if the amount is not much, it has no clinical significance.