Background:Patients operated on for gallstone disease often receive prophylactic antibiotics especially in acute operations but frequently also in elective surgery even though evidence for the effectiveness of such treatment is lacking. In this study we present data on the use of prophylactic antibiotics and postoperative infections from a national, web based register of gallstone surgery. Methods:The Swedish Register for Gallstone Surgery and ERCP (GallRiks) started in May 2005 and soon reached a national coverage with 75% of all procedures being entered in 2007. It comprises open and laparoscopic surgery of the gallbladder as well as all endoscopic interventions of the bile ducts. GallRiks is an internet application with on line registration of procedures and follow up as well as electronic reports on demand. A program for validation of data has started and the results from the first 6 hospitals revised indicate a match between the medical records and the database in 98.6% of the cases. During 2006 and 2007 a total of 16400 operations were registered in GallRiks. Patients from hospitals who had registered less than 25 patients were excluded from this study as were patients who had either a major surgery along with the cholecystectomy or only had a choledochotomy (previous cholecystectomy). Incomplete records and cases with a missing 30-day follow up were also excluded. Altogether 747 patients (4.6%) were excluded for these reasons. In another 4726 patients (30%) the surgery was performed acute. Thus, this is a study of 10927 patients who had an elective cholecystectomy performed in 54 Swedish hospitals during the years 2006 and 2007. Results:The 54 hospitals used prophylactic antibiotics at very different rates, from 0% to 98% of the operations, which by far exceeds any random variation. A postoperative abscess was found in 93 (.9%) and in 377 patients (3.5%) some kind of septic complication occurred requiring antibiotic treatment. In a multiple logistic regression analysis, adjusting for age, sex, indications for surgery, surgical methods and operative difficulties peroperative antibiotics had no beneficial effect on the risk of postoperative septic complications.Conclusion:There is a huge variation in the use of prophylactic antibiotics in elective cholecystectomy between different hospitals in Sweden reflecting the lack of uniform guidelines. The rate of septic complications from this operation is low and is furthermore unaffected by prophylactic antibiotics.