Just thought I'd add my experience. I had a ferret that had become ill. She was lethargic, losing weight, and grinding her teeth. I brought her to the vet, but they couldn't figure it out and at the time I didn't know much about ferrets. They told me to take her home and keep an eye on her. I brought her back about a week later because she wasn't getting any better. They took radiographs, did an ultrasound and finally drew some blood. Radiographs were normal, ultrasound revealed a mass behind the liver -- but they thought it might be the spleen because they couldn't find it. Unfortunately, when they took a blood sample, her blood was almost like water. Her PCV (packed cell volume) was less than 10%. I decided to have her euthanized. At necropsy they found a ruptured gastric ulcer with severe peritonitis. If caught early enough and treated, perhaps tragedy can be prevented. Lisa, Daisy and Squirt [Posted in FML issue 1629]