The dark blood you are getting in stools is altered blood, which comes high up in intestine or duodenum
NSAIDS type of drugs like paracitamol and nimuslide are potent gastric mucosa
irritators, as they remove the protective mucous layer of intestine, which becomes susceptible to acid burn of stomach.It is seen more often when drugs are taken empty stomach !!
I rather advice to stop those medications and take some ulcer healing m
edications. And if bleeding is not controlled , u shud go to casualty for furthur investigation.
hope my info helped you
Dr Hari Om Chandrakar