Postpolypectomy bleeding is the most common major complication following a colonoscopic polypectomy procedure. The incidence rate ranging from 0.3 to 6.1%. Several preventive methods such as detachable snare and adrenaline injection have been proposed in the management of postpolypectomy bleeding in large colonic polyps. It has been demonstrated that administration of ascorbic acid (vitamin C) in abdominal surgeries could reduce the blood loss during the procedure, operation time and days of hospitalization. So the investigators designed a prospective, randomized study to compares the efficacy of vitamin C administration with application of prophylactic clip and detachable snare in the prevention of postpolypectomy bleeding in large polyps.

In this prospective, randomized clinical trial, patients diagnosed with colon polyps with a diameter > 10 mm will randomized to receive either a 500 mg vitamin C in normal saline injection or a normal saline injection 2 hours before polypectomy. This administration will continued for 3 days after polypectomoy. Postpolypectomy bleeding is defined either as (1) early: occurring either during an endoscopic procedure or immediately after as hematochezia within 24 h or (2) delayed: any bleeding event that occurring between day 2 and day 30 following the polypectomy procedure.

Inclusion Criteria:

• Colorectal polyps larger than 10 mm.

Exclusion Criteria:

bleeding tendency poor preparation