I have irregular bowl movement. usually once every 2-3 days. when i finally go.. it's dark and smells fowl (more than uaual). also very gasy most of the time. could there be blood in my stool?

Blood in stool: It is possible. When stool is black, and pasty it is usually a sign of blood or when red. Occult/microscopic blood is harder to detect. There are tests for it. If foul smelling BM w/ gas may be food intolerance, gluten ,soy, may be gallbladder though usually have pain, or pancreas. Follow up with gastroenterology for hemoccult testing of stool and possible scoping.