The blood in stool
is due to infection in the digestive track or some liver
related issue. Your child needs to be investigated for that.
Give her a fiber rich diet, plenty of water, more green and leafy vegetables, avoid all fatty, oily, spicy food and avoid drinks which contain caffeine. Give her fresh food and juice.
Consult your doctor and get treated. Your doctor may give you a course of antibiotic and antacids.
Best Wishes and have a speedy recovery.