Background: A number of interventions have been used to decrease the incidence of post-operative paralytic ileus. A secondary outcome of a randomized controlled study showed that COX-2 inhibitors decreased the incidence of paralytic ileus. We sought to study a large cohort of patients undergoing major abdominal operations who were treated with a COX-2 inhibitor. Methods: This is a retrospective review of prospectively collected data. All eligible patients were given a COX-2 inhibitor - celecoxib 100mg - twice daily starting on the day of surgery until the seventh day post-operatively or discharge, whichever was earlier. The rate of paralytic ileus was calculated and compared with historical data. Secondary outcome measures were the effect of using COX-2 inhibitors on renal function, electrolytes and haemoglobin, morbidity and leak rates. Results: Two hundred and fifty-two patients were treated with celecoxib; the control arm consisted of 67 historical patients. Of the 252 patients, we had complete data for 235 patients and ileus in 17 patients (7.23%) compared with 13.4% in the control group (P=0.05). Subgroup analysis showed ileus in 5.45% of colectomy patients and 6.36% of patients who have had a colectomy and high anterior resection. There was no detriment of measured blood tests. There were leaks in two treated patients, both of whom did not require a laparotomy. Conclusions: The use of low-dose COX-2 inhibitor over a short period of time decreases the paralytic ileus rates and does not cause any significant morbidity.