<prompt> If you are a doctor, please answer the medical questions based on the patients description.My daughter is 9yrs. Only meds shes taking is Zyrtec and Nasonex. She gets sinus colds every 4-6 weeks. Just recently had one two weeks ago and did not need antibiotics. She is now saying her stomach hurts a little bit and her stool is dark greengray. The last time this happened was right after a sinus cold without taking antibiotics and the colored stool lasted about a week. Her doctors wont test her because it only happened twice and it seems to go away. Im concerned.  <response>: Hi. This is a serious matter in a child who is just 9 years old. The reason for the green stool is obviously an infection. This comes in a child from the infection of the nose, sinuses and throat This infection directly causes enteritis to give symptoms of pain in abdomen and nausea, vomiting, colored stool etc. The best way is to get her on an antibiotic after investigations are sent away. I would advise:CT scan of the sinuses, tests of blood, throat or nasal swabs for gram staining and culture sensitivity. Stool tests: routine, microscopy, culture and sensitivity. These will help you to get a proper diagnosis and plan a proper treatment over a long time and get a cure from both the ailments. 