Thank you for the query.
Both Encotrin and Prednisone
do affect stomach mucosa and can cause ulcers. And this can be the reason of black stools. However bleeding from stomach, duodenum
and small intestine
can all give black (tarry like stools), however encorton and aspirine gives only stomach and duodenum bleedings.
But in case of black stool there is no time for doubts about exact bleeding location, upper GI endoscopy
should be done as soon as possible.
Hope this will help.