Postoperative ileus (PI) is one of many common complications in major abdominal surgery. PI results in patient discomfort, increased gastrointestinal leakage, prolonged hospital stay, and increased medical expenses. In this study, we have investigated the morphine-sparing effects of ketorolac and its correlation with the duration of PI in patients with colorectal surgeries. We collected data from 102 patients who had received elective colorectal resection. The patients were randomly allocated into 2 groups and received intravenous patient-controlled analgesia (IVPCA) morphine (M group) or IVPCA morphine plus ketorolac (M+K group). Time-scale morphine consumption (per 12 h), recovery of bowel functions (the first bowel movement and passage of flatus), pain scores, and opioid-related side effects were then recorded. Patients in the M+K group received 18.3% less morphine than those in the M group within 72 postoperative hours. The maximal opioid-sparing effects of ketorolac appeared in 12 to 24 postoperative hours. The onset of the first bowel movement and passage of flatus was significantly less in the M+K group than in the M group. The M group showed a 5.25 times greater risk of inducing PI, a result comparable with the M+K group in colorectal surgery patients. The addition of ketorolac to IVPCA morphine has demonstrated a clear opioid-sparing effect and benefits in regards to the shortening of the duration of bowel immobility. We suggest that adding ketorolac to morphine IVPCA be included in the multimodal postoperative rehabilitation program for the early restoration of normal bowel function.