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.