The Blood in the stool may be due to many causes if it is fresh blood it may be due to Haemmorrhoids or anal fissure
It may be due to bleeding from the Gastrointestinal tract such as bleeding of an ulcer. The diseases that involve invaginating the gastric tract can have blood mixed with stool or blackening of the stool.
It may be due to variceal bleeding that may occurs in Chronic hepatitis
You should visit your surgeon to have proctoscopic examination to find the cause of bleed.
Have Blood CP to find the level of Hb in your blood if the bleeding is massive it can decrease your Hb levels.
I hope I am sucessful in solving your query If you have further you can ask me.
Dr. Azhar Sattar