Blood in the stool might be due to parasites, vitamin K deficiency, taking too many supplements like vitamin E or garlic that are anticoagulants, or hemorrhoids. If the blood in the stool is severe, then get help immediately. There also are some more serious causes of blood in the stool. I hope you aren't taking any aspirin, ibuprofin or acetaminophin on a regular basis, as these are also anticoagulants. Vitamin C in large quantities(more than a gram or two a day) can also act as an anticoagulant. vitamin E supplements are potent anticoagulants and should be avoided when there is blood in the stool.

So I suggest that you stop taking vitamin E supplements, cut out aspirin, ibuprofen and acetaminophen, and take vitamin K supplements(100 mcg twice a day?).