Blood in Stool: Differentiating Hemorrhage from Food

Blood in the stool?

Hello, doctor.
Thank you for your previous response.
I had a colonoscopy about two months ago, and it was normal.
I'm just curious about blood in the stool caused by internal hemorrhoids.
Can the blood mix with the stool? I've read online that it usually appears on the surface of the stool.
I mentioned before that I want to know how to distinguish between blood and food causing red stools.
I saw online that a method to differentiate is to check if it disperses in water; if it does, it's blood, and if it doesn't, it's food.
Does that mean if I use chopsticks to pick up the red part from the water and it doesn't disperse, then it's caused by food?

Xiao Jia, 20~29 year old female. Ask Date: 2015/08/13

Dr. Chen Qifeng reply Gastroenterology and Hepatology

Hello, the presence of blood in the stool, including its color and relationship with the stool, is primarily related to the volume of bleeding and the location of the bleeding.
Whether it disperses in water is just one method for reference; if necessary, a fecal occult blood test should still be utilized.
Sincerely, Dr.
Chi-Feng Chen, Attending Physician, Department of Gastroenterology, Taoyuan General Hospital, Ministry of Health and Welfare.

Reply Date: 2015/08/13

More Info

When it comes to identifying blood in stool versus food-related discoloration, it's essential to understand the underlying causes and characteristics of each. Blood in the stool can arise from various sources, including hemorrhoids, gastrointestinal bleeding, or other medical conditions, while certain foods can also cause changes in stool color.
In your case, since you have had a colonoscopy recently that showed normal results, it is less likely that you have a serious underlying condition. However, it is still important to monitor any changes in your stool and to differentiate between blood and food-related discoloration.

1. Characteristics of Blood in Stool: Blood can appear in different forms depending on where it originates in the gastrointestinal tract. Bright red blood typically indicates bleeding from the lower gastrointestinal tract, such as hemorrhoids or anal fissures. This blood may mix with the stool or appear on the surface. Dark red or maroon blood may suggest bleeding from higher up in the gastrointestinal tract, while black, tarry stools (melena) indicate bleeding from the upper GI tract, such as the stomach or duodenum.

2. Food-Related Discoloration: Certain foods can cause red or dark discoloration in stool. For example, beets, red gelatin, and some fruits like strawberries can lead to red stools, while iron supplements or foods like black licorice can cause black stools. The key to differentiating between blood and food is to consider your recent dietary intake.

3. Testing for Blood: The method you mentioned—placing the stool in water to see if the red color disperses—can be a helpful preliminary test. If the red color disperses in water, it is more likely to be food-related. However, this is not a definitive test. Blood tends to remain concentrated and may not disperse as easily.
4. Other Considerations: If you notice any significant changes in your bowel habits, such as persistent blood in the stool, changes in stool consistency, or accompanying symptoms like abdominal pain, weight loss, or fatigue, it is crucial to seek medical attention. A stool occult blood test can provide a more accurate assessment of whether blood is present in your stool.

5. Hemorrhoids and Blood in Stool: Regarding hemorrhoids, they can indeed cause blood to mix with stool, but it is often seen on the surface or as streaks. If you have hemorrhoids, you may notice bright red blood on toilet paper or in the toilet bowl after a bowel movement.
In summary, while the method of observing how the color behaves in water can provide some insight, it is not foolproof. If you are ever in doubt or if the symptoms persist, it is always best to consult with a healthcare professional for further evaluation and testing. Regular monitoring and maintaining a healthy diet can also help manage any gastrointestinal issues you may experience.

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