What Causes Blood in Stool?

Seeing blood in your stool is a symptom of a problem that may be benign or serious. Bloody stools are never normal, and you should have the issue evaluated by a doctor, especially if it is accompanied by other symptoms, such as rectal pain, constipation, abdominal cramps, and a feeling of your bowels not emptying.

A gastroenterologist can evaluate your rectum and anus and determine what is causing your symptoms. They may use a long, thin, lighted instrument to visualize your colon and/or rectum and recommend the appropriate treatment plan based on their diagnosis.

Here, we will talk about the possible causes of blood in the stool.


Hemorrhoids are enlarged veins around the anus and rectum, usually caused by constipation, straining during bowel movements, being sedentary, or pregnancy. Symptoms of hemorrhoids include itching, pain, and bleeding during bowel movements. Pain from hemorrhoids usually lasts for days. Blood from hemorrhoids is usually bright red since the swollen veins are in the anus and lower rectum and not higher up the colon. Complications associated with hemorrhoids are blood clots and infection.

Anal Fissures

Anal fissures are small tears in the lining of the anus or anal canal. The main symptom of an anal fissure is severe pain during and after bowel movements. Anal fissures typically occur when passing large or hard stools. Chronic constipation is often a contributing factor to anal fissures. Other possible causes include Crohn’s disease, diarrhea, and pregnancy. Symptoms may also include bleeding from the anus, itching, and a burning sensation in the area. Bleeding from anal fissures is usually accompanied by throbbing pain that lasts for a few hours. As with hemorrhoids, anal fissures can lead to infection or anal fistula, which is a tunnel that forms between the anus and the skin near the anus.

Colorectal Cancer

Colorectal cancer is thought to develop from a combination of genetic and lifestyle factors. Some inherited conditions, such as familial adenomatous polyposis (FAP) and Lynch syndrome, can increase risk of developing colorectal cancer. Other risk factors include being overweight or obese, smoking cigarettes, drinking alcohol excessively, having a diet high in red or processed meats, and having a history of inflammatory bowel disease (IBD).

Symptoms of colorectal cancer may include bleeding from the rectum or blood in the stool, changes in bowel habits, abdominal pain, fatigue, weight loss, and anemia. The most common symptom of colorectal cancer is bloody stool. This happens because the cancerous growths in the colon or rectum bleed. The blood can be fresh (bright red), or it can be old (dark in color).

Experienced Gastroenterologist in California

If you have blood in your stool, make an appointment with one of our gastroenterology (GI) doctors at Genensis Healthcare Partners, so they can determine the underlying cause of the symptom affecting your lower gastrointestinal tract and provide appropriate treatment. We have state-of-the-art screening and diagnostic tools that we use to evaluate patients and provide them with prompt and effective treatment. To schedule your visit, call our location nearest you or use our convenient online request form.