My five year old has lost seven pounds in the last 3 months due to chronic diarrhea. is this a dangerous amount of weight for her to have lost?

Significant-yes: The average 5 yo female weighs just above 40 lb and a 7 lb loss over 3 months is significant. It might not be dangerous in the short term, unless paired with unusual fluid losses, but deserves proper evaluation and treatment.Your PCP or pediatrician could start this but referral to a children's specialty center may be needed to track down the problem.