The objective of the work was to describe the basics of a meta-analysis with features for evaluating models with fixed and random effects, to present principles for interpreting the graphical results of a meta-analysis (forest plot or blobogram) of comparative reviews of randomized clinical trials (RCTs). Material and methods. To illustrate the possibility of efficient use of the R software environment for meta-analysis, we used the results of RCTs of various tonsillectomy methods already published in the Cochrane Database review. Results. The article provides explanations for the calculation of effect size, heterogeneity statistic, and other meta-analysis statistics and their interpretation for evaluating RCTs and recommendations for choosing a model depending on the on the general research concept. Conclusion. The described method allows meta-analysis and gives an idea of the principles for preparing the results of clinical trials with the expectation of their subsequent use in systematic reviews and meta-analysis.