The aim of the present study was to evaluate the effect of hyperbaric oxygen therapy (HBO2) on the healing process of ischemic colonic anastomoses in rats. Forty Wistar rats were divided into four groups: control (Group I), control and HBO2 (Group II), ischemia (Group III), ischemia and HBO2 (Group IV). Ischemia was achieved by clamping four centimeters of the colonic arcade. On the eighth therapy day, the anastomotic region was removed for quantification of hydroxyproline and immunohistochemical determination of metalloproteinases 1 and 9 (MMP1, MMP9). The immunohistochemical studies showed significantly larger metalloproteinase-labeled areas in Group IV compared with Group III for both MMP1 and MMP9 (p < 0.01). This finding points to a higher remodeling activity of the anastomoses in this experimental group. Additionally, animals subjected to hyperbaric oxygen therapy showed both a reduction in interstitial edema and an increase in hydroxyproline concentrations [at the anastomotic site]. Therefore, we conclude that HBO2 is indeed beneficial in anastomotic ischemia.