Russ and Scooter, >thin and dark stool over the past few weeks >somtimes its larger then normal and then it issmall and dark There are several diseases that can cause this; 1) Dietary indiscretion-- if he is eating somthing that is causing irratation to his GI tract 2) GI ulcers-- there is usually an underlying bacterial infection. The symptoms can include one or more of the following: loose stool, dark stool(it contains digested blood), poor appetite, weight loss. 3) Eosinophilic gastroenteritis-- this is less common and usually the is not blood in the stool. On a blood test the albumin is usually low and eosinophil (a type of white blood cell) count is up. 4) GI parasites-- this is less common, but giardia and coccidia can cause this. 5) Lymphsarcoma-- this can present this way and as it progresses will cause weight loss, poor appetite. On a blood test the lymphocyte count is usually high (a type of WBC) As you can see there are many potential causes. I would recommend you see your vet and they perform a good physical (and bring them a fecal sample of at least the abnormal dark stool for a routine micro exam and an occult blood--a chemical test for blood), and at least a CBC blood test. Good Luck, Dr Weiss 301-299-4142 [log in to unmask] [Posted in FML issue 1118]