The use of polyglactin 910 (Vicryl) in colonic anastomoses is theoretically undesirable because its short dissolution time and multifilament structure may lead to local sepsis and anastomotic leakage. We have compared Vicryl with a newly introduced monofilament absorbable suture which has a longer dissolution time than Vicryl. In a study of 98 rat colonic anastomoses no difference was found in complication rates or cellular reaction to the suture material between Vicryl and polydioxanone (PDS). The use of monofilament suture with longer dissolution time does not necessarily imply added security for colonic anastomoses.