19 year old daughter came home from work early, thought she d eaten something bad because of severe stomach upset & nausea . 3 hours later, had watery brown diarrhea , then puked once, got normal amount, but black-purple vomit . I saw some tarry black on the tissue when she blew her nose after. Now, she says the stomach pain is as bad or worse than she s ever had.
Hi welcome to Chat Doctor forum.  Thanks for choosing Chat Doctor. F.  As you describe your 19-year daughter had stomach pain, watery brown diarrhea, black purple vomit, When she blows tarry black on the tissue.  The description suggests that there is heavy infection in the intestines, with probable blood losing in intestines, it happens when there is much cramping or more infection. Nasal discharge this coloration is secondary to the regurgitation of the black vomit.  If the infection is controlled effectively every thing will be cleared. So I advise you to consult a physician for diagnosis and treatment.  Wishing for a quick recovery.  Best regards.