The present clinical study had the objective to evaluate the role of a hypertonic solution of sterile water from the Adriatic Sea in the prevention and treatment of chronic adenoiditis in children. It included 30 children aged from 2.5 to 15 years. The control group was comprised of 30 children treated by intransal drop infusion of physiological saline followed by irrigation of the nasal cavity with framicetin as recommended by the manufacturer. The study failed to reveal a significant difference (P > 0.05) between dynamics of the symptoms of chronic adenoiditis in the patients of either group assessed based on the 10-point analog visual scale. However, the frequency of relapses of adenoiditis during the observation period (3 months) was significantly lower in the patients treated with the hypertonic solution of sterile seawater. Microbiological investigations of the material from the pharyngonasal cavity showed no difference between the occurrence of tansient bacterial microflora in the patients of the study and control groups.