PURPOSE:Postoperative adhesions are a significant problem after colorectal surgery. However, the basic epidemiology and clinical burden are unknown. The Surgical and Clinical Adhesions Research Study has investigated the scale of the problem in a population of 5 million.METHODS:Validated data from the Scottish National Health Service Medical Record Linkage Database were used to define a cohort of 12,584 patients undergoing open lower abdominal surgery in 1986. Readmissions for potential adhesion‐related disease in the subsequent ten years were analyzed. The methodology was conservative in interpreting adhesion‐related disease.RESULTS:In the study cohort 32.6 percent of patients were readmitted a mean of 2.2 times in the subsequent ten years for a potential adhesion‐related problem. Although 25.4 percent of readmissions were in the first postoperative year, they continued steadily throughout the study period. After open lower abdominal surgery 7.3 percent (643) of readmissions (8,861) were directly related to adhesions. This varied according to operation site: colon (7.1 percent), rectum (8.8 percent), and small intestine (7.6 percent). The readmission rate was assessed to provide an indicator of relative risk of adhesion‐related problems after initial surgery. The overall average rate of readmissions was 70.4 per 100 initial operations, with 5.1 directly related to adhesions. This rose to 116.4 and 116.5, respectively, after colonic or rectal surgery—with 8.2 and 10.3 directly related to adhesions.CONCLUSIONS:There is a high relative risk of adhesion‐related problems after open lower abdominal surgery and a correspondingly high workload associated with these readmissions. This is influenced by the initial site of surgery, colon and rectum having both the greatest impact on workload and highest relative risk of directly adhesion‐related problems. The study provides sound justification for improved adhesion prevention strategies.