Can iron tables cause black runny stools and looks like coffee grounds? I been taking iron tablets for 2 days now and i notice my stools are black runny and looks like coffee grounds. I been having stomach problems for the past 3 months to where i am nauseated, lost of appetite diarrhea and constipation, burning stomach pains back aches, headaches, fatigue, shaken/weakness from not eating. Cant drink like us to, only take sips. I been X rayed, transvaginal ultrasound, blood, urine test. been diagnosed with GRED twice, depression, Irritable bowl syndrome twice, kidney infection. But now i notice this after i took a iron pill yesterday and today. what is wrong with me :(