Unfortunatly, my experince with histiocytic ulcerative colitis was not very good. My first boxer I ever had named Howie was diagnosed with it. He always had bloody, mucosy loose stools. I never saw him have normal poop. He had an endoscopy done with biopsy's when he was about 11 months old and that's how we knew for sure what was wrong with him. We tried EVERYTHING, different food, steroids, metranidazole, sulfasalazine, tylan powder, you name it, we tried it. He really never responed to any of it but we had the most luck with the steroids. He acted normal, was happy, playful, eating, and drinking ok but everytime he went to the bathroom he had the problems. He always maintained a good healthy weight. I did alot of reading about it when he was first diagnosed and everything I read was very discouraging. There is no cure, you can try to treat the symptoms but it's not always successful. Some dogs seem to respond better than others. Howie lived to be almost 1 1/2 years old before his body couldn't handle it anymore and he went to the bridge :( Sorry to be so down but I just wanted you to know my experiance with it. Hopefully your little girl will respond better than Howie did. We will keep her in our prayers and keep our fingers and paws crossed that you find somthing that works for her.