Hi, I am 16 male and have black stool ..second day with it, last night it was firm black stool with red blood around it. Today is black stool only, no blood. I have no abdominal pain but lots if presure and gas. I have no pain at all but I have not eaten iron, black berry juice, black licorice, nsaids, etc. I ate BBQ chicken and salad. Nothing abnormal. Thanks