Doctor Betti Dr. Betti Hertzberg Ressler is a Board Certified Pediatrician on staff at Miami Children's Hospital. Dr. Hertzberg developed the toilet training video "Let's Go Potty." She is the co-author of "The Doctor's Book of Home Remedies for Children." Constipation in babies Question: My son will be 3 weeks old on Thursday. I give him similac with iron and I also breastfeed but he seems to be constipated lately. The last time he passed a stool was yesterday in the morning and the color was greenish/mustard and it was almost like a diarrea. Should I give my son water? And if I can is spring water ok to give him? - Jennifer Answer: Constipation is defined as stool that is hard (consistency)and difficult to pass. It does not necessarily relate to the frequency or times that stool is passed. Some breastfed babies pass stool once in 4 to 5 days! Color of stool may vary from day to day. It may also vary with different foods that are eaten. Breast milk has natural laxatives, which prevent babies who are strictly breastfed from becoming constipated. By adding a formula such as Similac, consistency of the stool will also change. Breast stools are usually very mushy and sometimes almost liquid. Your diet will also effect your baby's stools. Water given in small amounts BETWEEN feedings (not in place of), is fine. Some pediatricians do not encourage water in breastfed babies. Others feel it would not hurt, if all else is fine. Check to see what your pediatrician recommends. The so called "nipple confusion" is behind this thought! In the first few months, cool (boiled) water or bottled water is fine. Spring water is fine also, but avoid giving your baby mineral water. It has a high mineral content. Your baby's kidney's are not equipped to handle it. Enjoy your baby and have a balanced diet yourself. Drink plenty of liquids in variety. Dr. Betti Also see: What is the cause of ITP and is there anything that can prevent it from recurring? Can a pediatrician comfortably prescribe and manage ADHD medication or is it better suited to a psychiatrist? Ask Dr. Betti your questions This information is not intended to be a substitute for visiting your pediatrician. If you or your child has specific concerns, you should see your doctor for a diagnosis and treatment.