Mechanical strength of the small intestinal wall 3.5 mm from an anastomosis was studied during the first week of healing and correlated to alterations in collagen content. The mechanical properties of the small intestinal wall 3.5 mm from the primary anastomosis remained constant during the first 3 days of healing. A previously observed decrease in suture-holding capacity of the small intestinal wall thus is a very local process extending less than 3.5 mm from the transection line. After 1 week of healing, the increase of suture-holding capacity correlated well with the increase in collagen content of the bowel wall.