this has happened a few times wi my dog the last was the worse she had in intestine infection, this can also happen through stress or upset but deffo best to get it checked
apparently the food i was giving mad wasn doin her anygood cause she has a sensitive stomach
ChiGM is right, blood in the stool is a symptom that needs to be evaluated by the vet soon. We just had a lab go through this and a round of antibiotics cleared it up.
Hopefully the vet will exam the situation as give a professional perspective on your friend's pet...
Please keep us posted,,no, its not good for blood in the stool.
And, welcome to the pet forum..