The purpose of this study is to perform a comparative analysis of the quantitative characteristics of the inflammatory response in the tissues of the lungs, pleura and adjacent subpleural areas of the chest wall to chemical pleurodesis using solutions of 4% sodium bicarbonate and 6% hydrogen peroxide in the experiment. An experiment was performed on 150 experimental animals (rats) in which spontaneous pneumothorax was modeled. Subsequently, after 1 hour, a solution of 4% sodium bicarbonate or 6% hydrogen peroxide was sprayed. The calculation of key statistical parameters of the presented data was carried out using descriptive statistic methods. The studied samples were evaluated using the Kruskal-Wallis test. Differences in the compared samples were considered significant at p ≤ 0.05. In both comparison groups, the predominance of neutrophils in the first days of the experiment was revealed, which indicates an acute inflammatory reaction to the chemical agent introduction. In the following days of the experiment, a decrease in the number of neutrophilic leukocytes was observed, simultaneously with an increase in the number of lymphocytes, macrophages, histiocytes, which indicated the transition of acute to chronic inflammation. It was established that the pleurodesis method has a statistically significant effect on the number of free cellular elements involved in the inflammatory reaction, despite the stereotype of the very dynamics of free cellular elements in all comparison groups. During chemical pleurodesis using a 6% hydrogen peroxide solution, the signs of acute inflammatory reaction from the pleura and the adjacent chest wall areas in experimental animals are shorter in time and not so intense compared to the similar group where a solution of 4% sodium bicarbonate was used.