BACKGROUND: The most common cause of intra-abdominal adhesion (IAA) is previous abdominal surgery and mortality. IAA can cause serious complications such as chronic abdominal pain, ileus, and infertility. Approximately 3% of all laparotomies are related to adhesions. IAA reduces the quality of life of the patient, causes morbidity, and increases health expenditures. In this study, we aimed to investigate the preventive effect of fucoxanthin (Fx) on IAA in the intra-abdominal surgical adhesion model that experimentally created in rats. METHODS: This study used 21 Sprague-Dawley rats divided into three groups. After anesthesia, the abdomen was opened, the cecum and right abdominal wall were damaged with a sterile toothbrush until petechiae bleeding was seen. No additional action was taken to the control group. In the sham group, 5 cc saline solution was released into the peritoneum before the abdomen was closed. In the Fx group, 35 mg/kg Fx was instilled intraperitoneally and the abdomen was closed. On the 21 st post-operative day, all subjects were anesthetized with standard anesthesia. Macroscopic adhesions were quantitatively evaluated according to the Mazuji classifica- tion. The cecum anterior wall and parietal peritoneum were excised for pathological sampling. A pathologist, unaware of the groups, evaluated inflammation, fibroblastic activity, and vascular proliferation. In addition, serum tumor necrosis factor-alpha (TNF-α) and interleukin-10 levels were measured. RESULTS: No rat was lost during the study period. Congenital adhesion was not observed in any of the subjects at the first laparo- tomy. Adhesion was significantly less macroscopically in the Fx group compared to the control and sham group (p<0.001 and p<0.001). Fibroblastic activity was found to be significantly less in the Fx group compared to the sham and control groups (p<0.001 and p<0.001). Vascular proliferation was found to be significantly less in the Fx group than in the sham and control groups (p<0.001 and p<0.001). The inflammation score was significantly lower in the Fx group compared to the other two groups (p<0.001 and p<0.001). The inflam- mation score in the sham group was lower than the control group and was statistically significant (p<0.001). TNF-α level was found to be statistically significantly lower in the Fx group compared to the sham and control groups (p<0.001 and p<0.001). CONCLUSION: As a result of experimental study, we can say that Fx is effective in preventing IAAs and decreases the level of TNF-α, a pro-inflammatory cytokine.