The mechanism of postoperative adhesion formation and prevention of adhesions are not clear, but the extent of adhesions of intestinal surfaces may be reduced with the various methods, such as minimal intestinal injury, prevention of coagulation of exudate, separation of prolonged contact of intestinal surfaces, removal of the fibrin and inhibition of fibroblast proliferation. Dextran has been used to prevent intestinal adhesions by means of floating bath and siliconizing effect in various experiments. In the gross findings, andhesions are classified into degrees as follows: Grade 0 : No adhesions Grade 1 : A single thin, easily separated Grade 2 : Two thin, easily separated Grade 3 : Numerous, thick, sharp lysed Grade 4 : Numerous, extensive, dense adhesions, resection needed In the pathologic findings, fibrinocollagen deposition, granulation, capillary proliferation, lymphocyte infiltration, edema and congestion are graded as mild(+), moderate and severe.(+++). The degree of adhesion were measured in 60 whit rats dividing into four equal groups at postoperative 1st week, 2nd week and 3rd week. Four groups were control group and intraperitoneal application groups with heparin, solumedrol and dextran respectively. The following results were obtained. 1) No significant differences in the degrees of adhesions were demonstrated among the four groups at postoperative 1st, 2nd and 3rd week. 2) The degrees of adhesion were significantly decreased in dextran group more than that of other groups at postoperative 1st, 2nd and 3rd week. 3) The changes of pathologic findings were more severe in postoperative 3rd week than that of 1st and 2nd week. 4) The gross and pathologic findings were correlated at same week each group. 5) The pathologic changes were decreased in dextran group more than that of other groups. In conclusion, the application of dextran was very useful for prevention of postoperative adhesions, and it should be opened for further study in large experimental group.