This study investigates whether oral acetaminophen, when added to standard pain management, reduces opioid use and pain after major abdominal surgery, compared to a placebo (inactive pill). Patients undergoing planned abdominal surgery under general anesthesia will be randomly assigned to receive either acetaminophen or a placebo tablet before surgery and every 6 hours afterward for 48 hours, in addition to their usual pain medication. Researchers will measure how much opioid pain medication patients need, how much pain they report, and how satisfied they are with their pain control during the first two days after surgery. The goal is to determine whether oral acetaminophen provides a genuine benefit beyond placebo in reducing opioid use while maintaining adequate pain control.