Hi & Welcome.
I appreciate your concern for passing dark blood like stools.
Incomplete date like age, gender, drug intake, any history of disease of the intestinal system, any associated symptoms or
weight loss,
The drugs mentioned 02 (
Ornidazole and Ofloxacin) or Rifaximine are effective only for diarrhea caused by bacteria or protozoa.
Most common causes of dark colored stool include bleeding from
peptic ulcer,
ulcerative colitis, hemorrhoids, polyps or any cancer involving the intestines.
I would advise you to consult a surgeon for proper clinical examination and relevant lab tests like stool analysis,
colonoscopy, tests for clotting, etc.
Hope I could answer your query.
A feed back is appreciated.