Aim. To conduct a comparative analysis of the effectiveness of lactulose and lactitol for the treatment of chronic constipation in children.Methods. 30 patients of the diagnostic unit of Children’s republican clinical hospital, Kazan, were randomly divided into 2 groups of 15 children matched by gender and age. Patients from group 1 were prescribed lactulose as a baseline therapy, and patients from group 2 were prescribed lactitol according to their age dose from day 1 of hospital stay with the assessment of the effectiveness on day 10 at discharge. Statistical processing of the results of research was conducted with the use of the program Biostatistica (S.A. Glantz, McGraw Hill) and spreadsheet editor Microsoft Excel 2003. The reliability of the data was calculated by methods of variation statistics. To compare performance when receiving lactulose and lactitol, paired Student’s t-test was used in case of normal distribution and Wilcoxon test was applied in case of skewed distribution. Pearson criterion was used to evaluate the correlation in case of normal distribution of the compared variables, and calculation of Spearman’s rank correlation coefficient was performed in all other cases. The differences were considered statistically significant at p 0.05.Results. As a result of hospital treatment, clinical improvement was observed in the majority of children in both groups. More than half of the subjects regardless of the choice of the osmotic laxative developed regular bowel movements and soft stools during hospital stay. Adverse effects occurred in a small percentage of subjects.Conclusions. The conducted study of efficacy and safety of lactulose and lactitol in children with chronic constipation confirmed similar efficacy and safety of these medications that allows recommending lactitol for widespread use in clinical practice.