Background/aims: Many studies have reported image analysis techniques, such as nuclear morphometry, counting or calculating of mitotic figures or estimation of the ratio of positive-stained areas immunohistochemically. The esophagus is the most commonly involved organ during caustic ingestion, which leads to progressive and devastating results after caustic burn. The aim of this work was to compare the classical stenosis index method with a new objective method based on image analysis that was used to determine experimental stricture of the rat esophagus. Methods: We investigated this technique by randomly allocating 20 rats each to sham laparotomy and corrosive esophagus groups. The images of the sham laparotomy group and corrosive esophagus group were reviewed, analyzed and used in a mathematical operation on the computer. The numbers and the ratio of luminal area and total esophageal area were used to determine the esophageal stricture of the rat, and results were compared with stenosis index ratios. Results: The mean area of the lumen of the esophagus and the ratio of esophageal lumen/total esophageal area were 0.83 (0.51-1.28) mm(2) and 0.21 (0.08-0.37), respectively, in the corrosive esophagus group. In the sham toparotomy group, these values were 1.28 (0.47-3.03) mm(2) and 0.26 (0.13-0.92), respectively. The differences between the two groups in luminal area and ratio of esophageal lumen/total esophageal area were statistically significant (p<0.05). Conclusions: This new technique based on image analysis seems more objective and reproducible than the classical, manual method. It is concluded that the use of this new technique dramatically reduced the subjectivity of the measurement process.