Introduction: Background/Aim: Emergency resections for colonic obstruction are accompanied with increased risk of anastomotic leakage. Up to date the effect of intestinal obstruction on collagen metabolism is poorly understood. We have determined the collagen concentration by means of appreciation of the hydroxyproline concentration in a rat model of left-sided colonic obstruction. Material and Methods: Colonic obstruction was induced in 17 Wistar rats of both sexes by applying two ligatures completely obstructing the colon 10mm from each other, three animals were used as controls, receiving manipulations on the left colon. Twenty four hours later three colonic specimens proximal, from the ligature zone and distal to this site and from equivalent regions in the controls were assayed for hydroxyproline concentration. Results: The hydroxyproline concentration (mean (s.d.) mg/g) was elevated in obstructed rats, but mostly in the distal segment when compared with the proximal region and the controls (proximal –0.52(0.03); stenotic–0.67(0.04); distal–0.84(0.004); controls 0.29(0.06) (NS). Conclusions: Our data suggest that obstruction positively affects the collagen metabolism, predominantly distally to the ligature site. Although the differences in hydroxyproline concentrations in controls and different obstructed colonic sites were insignificant, we assume that obstructed colon may possess an enhanced capacity to hold sutures.