What is the difference between rectal bleeding caused by colorectal cancer and rectal bleeding caused by hemorrhoids?
Jul 15, 2025
Source: Cainiu Health
Dr. Li Jingxiang
Introduction
In general, there are clear differences between rectal bleeding caused by colorectal cancer and that caused by hemorrhoids in terms of blood color, accompanying substances, relation to stool, frequency of occurrence, and associated symptoms. In daily life, if rectal bleeding occurs, one can make a preliminary judgment by observing these differences. At the same time, it is important to maintain good dietary habits and consume more foods rich in dietary fiber.
Generally, there are clear differences between rectal cancer-related hematochezia and hemorrhoid-related hematochezia in terms of blood color, accompanying substances, relation to stool, frequency of occurrence, and associated symptoms. A detailed analysis is as follows:
1. Blood color: Hemorrhoidal bleeding typically presents as bright red blood. This is because the bleeding site is close to the anus, and the blood flows out quickly without prolonged exposure, maintaining its original color. In contrast, rectal cancer-related bleeding is often dark red or jam-colored. Since the bleeding site in rectal cancer is deeper within the intestine, the blood remains in the intestinal tract for a longer time, undergoing oxidation that changes its color. Occasionally, bright red blood may also appear, but this is relatively rare.
2. Accompanying substances: Hemorrhoidal bleeding typically consists solely of blood without other abnormal substances. The blood is pure, consistent with the characteristic of direct venous rupture in hemorrhoids. In contrast, rectal cancer-related bleeding is often accompanied by mucus, pus, or necrotic tissue. As rectal cancer is a malignant tumor within the intestine, tumor ulceration and bleeding may mix with tumor secretions, dead cancerous tissue, and purulent material from the intestine, making the blood in the stool appear turbid.
3. Relation to stool: With hemorrhoidal bleeding, blood typically adheres to the surface of the stool or drips onto it after defecation, remaining separate from the stool itself. This occurs because hemorrhoids are located near the anus, and the bleeding happens after stool formation. In rectal cancer, the blood usually mixes thoroughly with the stool, forming purulent bloody stool or mucus-blood mixture. This is because the bleeding site in rectal cancer is within the intestine, where blood mixes with stool during its formation.
4. Frequency of occurrence: Hemorrhoidal bleeding is usually intermittent, often occurring after constipation, alcohol consumption, or ingestion of spicy or irritating foods. It can resolve spontaneously after rest or dietary adjustments, with irregular intervals between episodes. Rectal cancer-related bleeding tends to be persistent or recurrent. As the disease progresses, the bleeding becomes increasingly frequent and does not significantly improve with dietary changes or rest, lasting for prolonged periods.
5. Associated symptoms: Hemorrhoidal bleeding is usually accompanied only by localized symptoms such as anal pain, itching, and prolapse of hemorrhoids, without significant changes in bowel function. In contrast, rectal cancer-related bleeding, in addition to abnormal blood in the stool, is often accompanied by changes in bowel habits, such as increased frequency of defecation, alternating diarrhea and constipation, and changes in stool shape, such as thinning or deformation. Other possible symptoms include abdominal pain, abdominal mass, and weight loss.
In daily life, if hematochezia occurs, an initial judgment can be made by observing these differences. At the same time, maintaining good dietary habits, consuming more fiber-rich foods, and ensuring regular bowel movements can help reduce intestinal irritation and promote intestinal health.
