Constipation and blood in the stool can occur at the same time, due to many different reasons. For most people, blood in stool may occur due to issues with bowel movements, tears to the anus, or hemorrhoids.

Constipation refers to infrequent and uncomfortable bowel movements. A person has constipation when they pass small amounts of hard, dry stool less than three times a week. The stool is painful to pass sometimes, and people often feel they cannot empty the stool from their rectum completely.

People may have constipation for many reasons. Sometimes, there is no apparent reason. It commonly happens when stool moves too slowly through the digestive tract due to less water consumption, dietary changes, or decreased activity. The slower stool movement increases water absorption from the stool, making it hard and dry and more difficult to eliminate from the rectum.

Chronic constipation has several potential causes and can lead to various complications that may result in bleeding.

This article examines whether constipation can lead to blood in stools. We discuss the associated symptoms of rectal bleeding from constipation and how to treat it. We also look at some frequently asked questions on the subject.

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Although it is not common and does not occur in everyone, people may experience blood in their stool with constipation for the following reasons:

Anal fissure

An anal fissure is a tear or ulcer that develops in the tissue that lines the anus. Anal fissures are common in people with constipation. They often occur when people strain to pass hard or large stools during a bowel movement.

Anal fissures tend to cause sharp rectal pain with bowel movements and some rectal bleeding. They can be acute and last for less than 6 weeks or chronic, lasting more than 6 weeks.


Hemorrhoids are swollen and inflamed blood vessels that can develop externally under the skin around the anus or internally in the lining of the anus or lower rectum. Hemorrhoids are common, affecting around 1 in 20 people in the United States.

People are more likely to develop hemorrhoids with increased pressure in the lower rectum. Increased lower rectal pressure could occur due to the following:

  • straining during bowel movements
  • passing hard stools
  • having chronic constipation

Due to their rich vascular supply, hemorrhoids often bleed, causing bright red blood to coat the stool, drip into the toilet, or be visible on toilet tissue. Hemorrhoids are the most common reason for rectal bleeding.

Fecal impaction

Fecal impaction occurs when stool becomes hard and dry and gets stuck in the colon. An impacted colon blocks the way for waste to leave the body and instead makes it way back inside the large intestine, causing increased gastrointestinal pressure and discomfort.

Most people with fecal impaction have chronic constipation. Rectal bleeding is a common symptom of fecal impaction.

Other conditions

Several other conditions are associated with constipation and may cause blood in bowel movements. These include the following:

  • Rectal prolapse: This occurs when the lowest part of the large intestine slides out through the anus, producing a lump. People with rectal prolapse may experience constipation and pass blood from the rectum.
  • Colon cancer: This cancer usually begins as noncancerous clumps of cells called polyps inside the colon. Over time, some polyps can become cancerous. Colon cancer may cause persistent changes in bowel habits, rectal bleeding, and blood in the stool.
  • Diverticular diseases: Diverticular diseases occur when multiple small pouches — diverticula — develop and push outward through weak areas in the colon wall, leading to inflammation in some people. Blood vessels in the wall of the pouches can become brittle with time, making them rupture and bleed. Diverticular disease can also lead to constipation.
  • Abdominal cancer: Abdominal tumors can narrow the bowel and rectum, making it difficult for someone to have a bowel movement and causing constipation. These tumors may also cause blood in stool.
  • Rectal cancer: This begins in the rectum and may cause bowel changes, such as constipation and blood in stool.
  • Chronic inflammatory conditions: This can include inflammatory bowel diseases, such as Crohn’s disease and ulcerative colitis, among others.

Symptoms can vary according to the cause of constipation and rectal bleeding. Aside from the symptoms listed above, others may include:

If people are concerned about their symptoms, they should contact a healthcare professional as soon as possible to rule out severe conditions.

If anal fissures, hemorrhoids, or other conditions are causing constipation and bleeding, a doctor will treat the specific cause of the symptoms. Overall, treatments aim to:

  • improve bowel movements
  • stop bleeding
  • relieve any associated symptoms

A doctor may recommend the following strategies for constipation:

  • Eating 28–34 grams of fiber daily to keep stool soft and improve fissure healing.
  • Drinking enough fluids to prevent constipation.
  • Avoiding straining during bowel movements because the pressure can cause new tears or open a healing tear.
  • Taking fiber supplements such as methylcellulose (Citrucel) or psyllium (Metamucil).
  • Trying stool softeners, such as docusate (Colace).
  • Using stimulant laxatives, such as bisacodyl (Dulcolax).
  • Trying prescription medications, such as lubiprostone (Amitiza), linaclotide (Linzess), or prucalopride (Motegrity).
  • Getting regular physical activity.
  • Trying bowel training. For example, aim to have a bowel movement 15–45 minutes after breakfast, as eating helps move stool.

Below are some common questions and answers on the topic:

How do doctors evaluate blood in stool?

A doctor will first take a medical history. They will likely ask questions such as the amount of blood visible and when symptoms began, among others. A physical examination may be necessary, which may involve a rectal exam.

Further testing, if indicated, may involve blood tests and upper endoscopy or colonoscopy.

Learn more about diagnosing blood in stool.

Is bright red blood in stool serious?

A small amount of red blood from the anus that happens once or twice is not usually a sign of something serious and could result from constipation. This one-off bleeding will often resolve without treatment.

However, if bleeding lasts over a couple of days or is heavy and in multiple bowel movements, a person should consult a doctor. Some causes of rectal bleeding are serious and need urgent treatment.

When should I worry about blood in stool?

People should seek emergency help if they have the following symptoms of shock with rectal bleeding:

A person should attend the emergency room immediately if they have continuous or heavy rectal bleeding or rectal bleeding with severe abdominal pain and cramping.

People may experience constipation and blood in stool for many reasons, ranging from mild to severe. For most people, bleeding may occur due to issues with bowel movements, tears to the anus, or hemorrhoids, and it can improve with home treatments.

Some causes of constipation and rectal bleeding are severe and require prescription treatments and, in some cases, surgery. Severe causes of constipation and bleeding may include conditions such as colon and rectal cancer.

A doctor should check rectal bleeding lasting more than a few days. If people have symptoms of shock with rectal bleeding, they should get immediate medical advice. They should go to the emergency room if bleeding is heavy, continuous, and with severe abdominal symptoms.