Hi. Thanks for your query. Noted the history and understood your concerns. Eating raspberries and getting black and res stool may be co-incidental as the fruits are not known to cause bleeding in the gastrointestinal tract. I would advise you the following in such a situation: It is very important first to confirm whether there is any actual bleeding or that the color of raspberries is showing in the stool. Hence go for stool test for three consecutive days. Tests of blood. Get an appointment for an upper GI Endoscopy and Colonoscopy to find out if there is any cause for red and black stools and is spotting the underwear. Once confirmed get treated accordingly and most important stop eating raspberries or anything else with high iron contents. Also get an ultrasonography and other tests as needed or advised by your Doctor.