can ulcers cause black stools
Helicobacter pylori â sometimes called H. pylori or HP is a bacterium that causes ulcers. H. pylori is also a risk factor for stomach cancer. If prescribed, it is very important to complete an entire course of antibiotics for H. pylori. Melena â black very sticky stool, often compared to roof tar. This is a common symptom of a bleeding ulcer. Black stool that looks like melena can be caused by taking iron medications and by drugs like Pepto-Bismol Â® .