There are many reasons you may discover blood in your stool, and some of them are life threatening. Some are less so, but finding the cause is very important.
How do you know there's blood?
Seeing something red is one way, but that is not the only thing to watch for. If the blood has been in or through the stomach, it won't be red. It'll be black and have the consistency of tar or coffee grounds. Both types can be a sign of something bad.
What causes it?
1) Medications and herbs: Aspirin, willow bark and blood thinners can cause bleeding in the intestines. Anti-platelet medications can do the same thing. This is something you should speak to your doctor about, as you may need a change in these medications.
2) Ulcers: Whether it's in your stomach or your intestines, an ulcer can bleed. Stomach ulcers can cause this to exit on both ends of the alimentary canal. This is a potentially life threatening problem, so getting treatment fast is important.
3) Hemorrhoids: This burning, itching problem around the anus can actually rupture. If so, the color will be fairly bright red. Diverticulitis (an abnormal pocket in the intestines) can also bleed.
4) Crohn's Disease: Another name for this is ulcerative colitis, and as the name suggests it causes ulcers in the digestive tract.
5) Colon Cancer: This is obviously not something that can be treated at home, and one of its symptoms is bloody stools.
Some of these problems can be dealt with using herbal remedies and lifestyle changes. Others may need the help of your doctor, especially if cancer is the cause. It's always best to consult your doctor, especially in the above cases. The doctor can give you a diagnosis and help you come up with a plan that will be beneficial for you.
For ulcers and Crohn's Disease, you may be able to use marshmallow or licorice root to coat the digestive tract. You will probably also need an antibiotic, at least in the case of regular ulcers. Don't take any medications at the same time as the herbs, as it can prevent proper absorption. Don't use licorice root if you have high blood pressure.
Hemorrhoids may be eased by sitz baths, witch hazel and aloe vera. The witch hazel acts as an astringent, and may shrink the hemorrhoid. Aloe will help reduce inflammation. Don't drink the juice, as it can cause explosive diarrhea, which would be an irritant.
Colon cancer, as mentioned above, cannot be treated at home. If the doctor approves, oats and marshmallow may be useful. Due to the side effects, licorice root would be a bad idea.
There is one more thing to consider if you see an off-color stool. Some of the things we eat can change the color and not be a threat. Black licorice and pepto-bismol, lead, iron tablets and blueberries can turn the stool dark. Tomatoes can give a reddish color, especially if a great many are eaten.