Abstract: Objective: To investigate the effect of nitric oxide in preventing postoperative adhesions formation in traumatic mice.Methods: In the pre experimental group eight kunming mice were created cecal abrasion and parietal peritoneal defect with vefined Mazuji methods as experimental models and the effect of adhesion formation was observed.In the experimental group,seventy-two mice were divided into control group(Ⅰ),L-arginine group(Ⅱ) and NG nitroarginine methyl ester(L-NAME,Ⅲ) group.0.9% NaCl(Ⅰ),L-arginine(Ⅱ) and L-NAME(Ⅲ) were administered intraperitoneally before abdominal closure and 3 consecutive days after surgery.All the three groups were divided into three subgroups for evaluation of adhesion severity and serum nitric oxide(NO) levels at postoperative days 3,7 and 14.Adhesion severity was measured with adhesion grading(Nairs's standard)and tissue hydroxyproline(OHP) levels.Results: In the pre-experimental group,the adhesion rate was 100% in the eight mice two weeks after operation.All adhesions were middle or severe adhesion(3 to 4 grade) and the mean score was 3.50±0.53.In the experimental group,(1)the adhesion mean score and OHP levels were minimal and almost equal between the three groups at day 3(subgroup A)(P>0.05),while the adhesion mean score and OHP levels were higher in groupⅠand Ⅲ than in group Ⅱ at day 7(subgroup B) and 14(subgroup C)(P<0.01).The adhesion mean score and OHP levels were the highest in subgroup A,the lowest in subgroup C and the medium in subgroup B(P<0.01).Logistic regression analysis showed significant correlation between adhesion score and tissue OHP levels in subgroup B and C respectively(r_b=0.95, r_c=0.93, P<0.01).(2)NO level was higher in group Ⅱ than in groupⅠand group Ⅲ at day 3,7 and 14 respectively(P<0.01)and there was no difference between groupⅠand group Ⅲ(P>0.05).There was no difference between subgroup A,B and C(P>0.05).Conclusions: The intraperitoneal administration of L-arginine results in significantly higher serum nitric oxide levels and inhibits postoperative adhesion formation.