The dark brown color of the baby’s stool after changing milk powder may be related to indigestion after changing milk powder, or it may be caused by dietary factors, disease factors, and so on. 1. indigestion: the nutrients contained in different types of milk powder may be different, after changing milk powder, some babies may suffer from indigestion, manifested as dark brown stools. 2. Dietary factors: some babies have added complementary foods, if the complementary food for the liver, spinach soup and other foods, may also lead to changes in stool color. If you have dark brown stools after changing milk powder, it is recommended to take your baby to the hospital in time for routine stool examination and other items to clarify the cause under the guidance of a professional physician.