Why does one bleed from the rectum?

Rectal bleeding, also known as hematochezia, is a common symptom that can have a variety of causes. While some causes are relatively minor, others can be more serious and require medical attention. Common causes of rectal bleeding include:

1. Hemorrhoids: These are swollen veins in the lower rectum and anus. They are very common and typically cause painless bleeding.

2. Anal Fissures: These are small tears in the lining of the anal canal. They can cause intense pain and bleeding during bowel movements.

3. Diverticular Disease: This condition occurs when small pouches form in the large intestine. It can sometimes cause painless bleeding.

4. Colorectal Cancer: This is a type of cancer that starts in the colon or rectum. Rectal bleeding is a common early warning sign of this cancer.

5. Inflammatory Bowel Disease (IBD): This group of conditions includes Crohn's disease and ulcerative colitis. They can both cause diarrhea, abdominal pain, and rectal bleeding.

6. Ischemic Colitis: This occurs when there is a lack of blood flow to the colon. It can cause abdominal pain, constipation, and rectal bleeding.

7. Infectious Colitis: This is an infection of the colon. It can be caused by viruses, bacteria, or parasites. It can cause diarrhea, abdominal pain, and rectal bleeding.

8. Anorectal Trauma: Injury to the anus or rectum from trauma, such as a fall or insertion of a foreign object, can cause rectal bleeding.

9. Certain Medications: Some medications, such as aspirin, non-steroidal anti-inflammatory drugs (NSAIDs), and anticoagulants, can cause rectal bleeding.

10. Other Medical Conditions: Some other medical conditions, such as liver disease, kidney disease, and certain rare bleeding disorders, can cause rectal bleeding.

It is important to note that rectal bleeding does not always indicate a serious underlying medical condition. However, it is always best to consult a doctor for evaluation, especially if the bleeding is persistent, heavy, or accompanied by other symptoms such as changes in bowel habits, abdominal pain, or weight loss. The doctor can perform a physical examination, order diagnostic tests, and recommend treatment if necessary.