Hi. Thanks for your query. Noted the history about your 5 year old daughter having constipation, following Miralax protocol and had large hard light grey stool, wants to know about the significance of color. Worrying much about color is not needed in children as there are many factors that can change the color. To get a confirmed diagnosis I would advise you the following: Send the stool sample for tests on three consecutive days. Tess of blood Ultrasonography of the whole abdomen and X-ray of the abdomen will show if fecoliths are present or not. If present the child needs saline and soap enema for complete evacuation. Continue the Miralax protocol. Keep a strict watch on the foods and beverages that cause constipation and to strictly stool these. Appendicitis can cause loose stools and pan in abdomen with nausea, vomiting, fever and bloating; and particularly in children they cause need to go for passing stool after taking food.