what causes stool to be very dark in colour

[taffy79]

I have had very dark and small stools for a long time doctors done nothing about it

[Brochie]

Is it black tarry stool?
- could be ileocecal valve problems or Gd forbid cancer or iron supplements I think cause dark stool.    Do you notice blood in your stool bright red or do you wake up with urgency at night.   If yes see a different GI dr