Seeing blood in your stool can definitely set off alarm bells. Here's what you need to know about possible causes and when to see a doctor.

Seeing blood in your stool can understandably set your mind racing with worry. You might notice a small amount of blood on the toilet tissue or a red or maroon streak in your stool.

Is This an Emergency?

If you are experiencing serious medical symptoms, seek emergency treatment immediately.

Large amounts of fresh blood typically lead to burgundy-color stools or tinge the toilet water pink or red. Fresh blood in the stool usually indicates bleeding from the lower gastrointestinal (GI) tract, including the colon, rectum and anus.

Rarely, passage of fresh blood signals heavy bleeding from the upper GI tract — the esophagus, stomach and upper small bowel. More commonly, upper GI bleeding leads to black stool due to breakdown of the blood as it passes through the digestive system.

There are many possible causes of fresh blood in the stool (known medically as hematochezia, or rectal bleeding) caused by lower GI bleeding, ranging in severity from hemorrhoids to inflammatory bowel disease to cancer. If you notice blood in your stool, contact your doctor right away to determine the next steps.

1. Diverticulosis

Diverticuli are small pouches that project outward from the walls of the intestines. They most commonly develop toward the end of the large intestine, or colon.

The presence of multiple diverticuli in the colon, known as diverticulosis, most frequently affects older adults. Diverticulosis usually causes no symptoms. Painless bleeding, however, occurs in approximately 10 to 15 percent of people with the condition, according to the Merck Manual 16.

Diverticulosis is the leading cause of lower GI bleeding requiring hospitalization, as noted in a July 2013 Current Gastroenterology Reports review article 27. Mild abdominal cramps often precede the bleeding, followed by an urgent need to empty the bowels.

Most bleeding from diverticulosis stops spontaneously, but careful monitoring in the hospital is typically necessary. People with severe or persistent bleeding often require intravenous fluids, a blood transfusion and/or other treatments.

Read more: 7 Weird Facts About Poop

2. Hemorrhoids

Hemorrhoids are enlarged blood vessels in the lower rectum or anus. A March 2016 review article in the journal Clinics in Colon and Rectal Surgery reports that this common condition most frequently affects people ages 45 to 65, but can develop in adults of all ages 3.

Hemorrhoids are categorized by their severity and whether they occur internally, externally or both. Hemorrhoids can cause lower GI bleeding and usually arises from internal rather than external hemorrhoids. The amount of bleeding due to hemorrhoids varies from a streak on the toilet tissue to blood dripping into the commode after passing stool.

Minimal hemorrhoidal bleeding is typically treated with lifestyle changes, including increased dietary fiber and fluid intake. Significant or recurring bleeding due to internal hemorrhoids is usually treated with an ablation procedure, which destroys the hemorrhoidal tissue responsible for the bleeding.

3. Colonic Ischemia

Colonic ischemia (CI) refers to colon tissue damage triggered by reduced blood flow and an associated lack of oxygen. This situation is usually temporary, and the damage is typically limited to an isolated segment of the colon lining. CI commonly causes passage of bloody stool and primarily affects people age 50 or older.

A number of medical conditions increase the risk for CI, including diabetes, atherosclerosis, heart failure and chronic obstructive pulmonary disease.

Symptoms of CI vary, but many people experience sudden lower abdominal cramps accompanied by a strong urge to move the bowels. Bloody diarrhea or maroon or bright-red blood in stool typically follows within 24 hours of the initial symptoms.

Although colonic ischemia ranges in severity, most people do well with early diagnosis and medical treatment in the hospital. Immediate surgery is necessary if a segment of the bowel dies, a medical emergency known as gangrenous colitis.

4. Colonic Angiodysplasia

Angiodysplasia is a 10-dollar word that generically refers to a blood vessel abnormality. Colonic angiodysplasia describes a degenerative process in which the walls of previously healthy blood vessels in the colon weaken and thin over time. People with this condition usually have several abnormal blood vessels in their colon.

Most people with colonic angiodysplasia experience no bleeding or other symptoms. However, these thin-walled vessels sometimes bleed and cause fresh blood in the stool. Colonic angiodysplasia is the second most common cause of lower GI bleeding and fresh blood in the stool among seniors (behind diverticulosis) 5.

Bleeding from colonic angiodysplasia usually causes no pain or other symptoms, but it ranges from mild to severe and tends to recur. Treatment for bleeding from colonic angiodysplasia that doesn’t stop on its own usually involves destruction of the bleeding vessels. Medication and surgery may be recommended for some people.

5. Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) refers to Crohn disease and ulcerative colitis, conditions characterized by chronic GI tract inflammation. With Crohn disease, inflammation can develop anywhere along the GI tract. Inflammation is limited to the colon and rectum in people with ulcerative colitis.

Bloody stools, usually in the form of diarrhea, occur more commonly with ulcerative colitis, but also occur with Crohn disease involving the colon or rectum. Pus and mucus might also be present in the stool.

Other possible symptoms of IBD include abdominal pain, fever, weight loss and a persistent, urgent need to move the bowels. Most people with IBD experience cyclical flare-ups interspersed with periods of low disease activity.

IBD can occur at any age, but it’s most often diagnosed in people younger than 30. Medications to reduce inflammation and disease-related symptoms remain the mainstay of treatment for Crohn disease and ulcerative colitis.

Specific treatment recommendations depend on disease severity. Blood transfusions may be needed during periods of heavy bleeding. Surgery is sometimes recommended for people with severe disease or complications that cannot be managed with medical therapy.

Read more: 7 Signs Your Gut Is Out of Whack

6. Colorectal Polyps and Cancer

Colorectal polyps are growths that arise from the lining of the colon or rectum. Most aren’t cancerous, but these growths are important because some can become cancerous over time.

In fact, most cases of colorectal cancer arise from a polyp 6. Colorectal polyps and cancers vary in size and most cause no noticeable signs or symptoms until they become large. This is why colorectal cancer screening is so important.

Large polyps and colorectal cancers can bleed and cause fresh blood in the stool. Small amounts of blood are often detectable only with laboratory testing. Visible blood, however, is also possible. Bleeding from colorectal polyps or cancer typically causes no pain. Other symptoms are uncommon, although large growths sometimes cause diarrhea or constipation.

Colorectal polyps are typically removed during a colonoscopy procedure. Depending on the size and microscopic appearance of the removed polyps, doctors recommend repeat colonoscopy screening at varied time intervals. If colorectal cancer is detected, treatment may involve surgery, chemotherapy, radiotherapy or a combination of these treatments.

Other Causes of Blood in Stool

Many other conditions can lead to fresh blood in the stool, although they are less likely than the causes already discussed above.

1. Anal Fissures

Anal fissures are small tears of the anus, the opening through which stool passes from the body. They cause pain and a small amount of bleeding when passing stool. Most heal on their own, but longstanding or deep fissures can lead to anal ulcers, which also commonly bleed with bowel movements.

2. Infectious Proctitis

Infectious proctitis refers to an infection of the rectum, which can cause fresh blood in the stool. The condition is usually a sexually transmitted infection, most commonly caused by the bacteria responsible for gonorrhea and/or chlamydia. Other symptoms include rectal pain and anal discharge.

3. Infectious Colitis

Infectious colitis is a form of food poisoning that causes inflammation of the colon. Typical symptoms include watery diarrhea, which may be bloody, along with abdominal cramps and even fever. Common causes include certain strains of S_almonella_, Shigella, Campylobacter and E. coli bacteria.

4. Meckel Diverticulum

Meckel diverticulum is a pouch near the junction of the small and large intestines. It’s a remnant of the umbilical cord that is present from the time of birth in approximately 2 to 3 percent of people.

Most people with this condition never experience symptoms, but bleeding and bloody stools occur in a small portion of those affected. Symptoms due to Meckel diverticulum develop more commonly in children than adults.

5. Rectal Varices

Rectal varices are enlarged, fragile blood vessels in the rectum. They most often occur in people with cirrhosis due to a backup of blood caused by impaired blood flow through the liver. These fragile blood vessels can rupture and cause massive, life-threatening bleeding. Emergency treatment is needed to control bleeding from rectal varices.

6. Heavy Upper GI Bleeding

Heavy bleeding from the esophagus, stomach or small intestine sometimes cause bloody stools. Brisk upper GI bleeding causes the blood to move through the digestive system quickly, often appearing as bloody or maroon-color diarrhea. Possible causes include peptic ulcer disease, severe inflammation of the stomach and ruptured veins in the esophagus.

When to Call Your Doctor

  • Dizziness, lightheadedness or fainting
  • Rapid heart rate or breathing
  • Paleness
  • Cold, clammy skin
  • Low blood pressure
  • Agitation, confusion or drowsiness

What Do YOU Think?

Have you ever seen blood in your stool? What did you do? Did you consult your doctor? Did you discover the cause of the blood in your stool? What treatment did your doctor prescribe? Share your thoughts and questions in the comments below.