If bleeding per rectum is fresh blood then it is most likely lower GI bleeding due to Hemorrhoids or fissure in ano
or any mass lesion for which you may need
2. CT/MRI of the Abdomen
If you're passing black coloured stool then it may be due to upper GI bleeds and you may need
of the upper GIConsult a Gastroenterologist
On the other hand it may be due to Antibiotic induced Diarrhea
In that case Probiotics will help.