Thanks for writing to health care magic.
Blood in the stool could be because of several causes and one of them is dysentry
In such cases there will be improvement with antibiotics normally prescribed by doctors.
But if blood in the stool is because of some other cause there may not be any improvement in the condition with antibiotics.
The other causes could be anal fissure
, rectal polyp
So further investigations and examination are required in such scenario
Hope this helps