A colonoscopy examines the lining of the large intestine (colon) for screening, diagnosis, or to investigate gastrointestinal symptoms. A flexible tube called a colonoscope is inserted through the rectum, allowing a physician to view the inner surface of the colon. This enables the detection and removal of abnormal growths, such as polyps, which helps prevent and diagnose colorectal cancer early. Understanding the common after-effects helps patients manage their recovery.
Defining Normal Bleeding
Seeing blood after a colonoscopy can be alarming, but a small amount is often a normal part of the healing process. This minimal bleeding is generally confined to light streaks of bright red blood visible on the toilet paper after a bowel movement. It might also appear as a faint pink tinge in the toilet bowl water when you first pass stool following the procedure.
The quantity of blood should be minor and self-limiting, resolving on its own without intervention. Normal bleeding is defined by its fleeting nature and small volume, not exceeding more than a few drops or a teaspoon in total. This spotting is a common side effect, especially when the procedure involved removing tissue.
Why Bleeding Occurs
The presence of a small amount of blood relates directly to minor procedures performed inside the highly vascularized colon. If the physician takes a biopsy (a small tissue sample), it creates a superficial abrasion on the colon lining that may bleed lightly. Similarly, removing a polyp in a process called a polypectomy leaves a small wound site.
During a polypectomy, the physician uses a specialized tool, often with an electrical current (cauterization), to sever the polyp and seal the blood vessels at the base. This process prevents heavy bleeding, but the resulting wound needs time to heal. Even after successful cauterization, a protective scab forms over the site, and the natural shedding of this scab can lead to minor spotting days later. The size and location of the removed polyp influence the likelihood and amount of initial bleeding.
The Timeline of Post-Procedure Bleeding
For most patients, minor bleeding usually stops within the first 24 hours following the procedure. This immediate, light spotting is associated with initial wound sites created by biopsies or small polyps. The body’s natural clotting mechanisms quickly seal these minor surface irritations.
Delayed bleeding occurs after the initial 24-hour period, typically five to ten days after the colonoscopy, though sometimes up to two weeks later. This usually happens after a polypectomy when the protective scab covering the removal site naturally detaches from the colon wall. While often minor, this type of bleeding can seem sudden and may be more noticeable than the initial spotting. The risk of delayed bleeding is higher when larger polyps (over ten millimeters in size) were removed.
Warning Signs and When to Seek Help
While light spotting is expected, certain signs require immediate medical evaluation. Seek prompt attention if you pass large amounts of bright red blood or notice significant blood clots. Any continuous heavy bleeding or passing a volume of blood that exceeds about half a cup is a cause for concern.
Bleeding accompanied by severe systemic symptoms also signals a need for urgent care, as it may indicate a complication. These warning signs include severe, persistent abdominal pain, fever or chills, persistent dizziness, fainting, or a rapid heart rate. These symptoms can indicate significant blood loss or a rare infection. If any bleeding continues or worsens after the first few days, contact your healthcare provider immediately for guidance.