Aim. Comparative clinical study of hygienic dental product of plant origin based -mangostin [1,3,6-Trihydroxy-7-methoxy-2,8-bis(3-methyl-2-butenyl)-9H-xanthen-9-one], a xanthone from mangosteen fruit, having antimicrobial and anti-inflammatory activity in the treatment of chronic generalized catarrhal gingivitis. Methods. The study included 319 patients aged 22 to 45 years. All patients were divided into two groups: the control group 20 people (males 40%, females 60%), average age 34.88.00 years; the comparison group 20 people (males 45%, females 55%), average age 35.07.10 year; the main group 20 people (males 40%, females 60%), average age 34.97.86 years. There were no statistically significant differences between all groups (p 0.05). The nosological form of the disease in the studied patients is chronic generalized catarrhal gingivitis (K05.1). Treatment in all groups was carried out using the standard regimen of complex therapy of chronic generalized catarrhal gingivitis. Therapy of the main group patients was supplemented by the use of the hygienic gel containing 1% -mangostin [1,3,6-Trihydroxy-7-methoxy-2,8-bis(3-methyl-2-butenyl)-9H-xanthen-9-one], whereas treatment of the comparison group patients was supplemented by the complex preparation containing 1% metronidazole and 0.25% chlorhexidine digluconate. The dental examination included a questionnaire with the registration of subjective data (patient complaints) and objective data on the state of the tissues of the mouth (index score) before and after therapy, as well as the dynamics of the indicators fixing during the entire treatment. Results. The performing a comparative study of the treatment effectiveness of chronic generalized catarrhal gingivitis, using a dental hygienic gel containing 1% -mangostin [1,3,6-Trihydroxy-7-methoxy-2,8-bis(3-methyl-2-butenyl)-9H-xanthen-9-one] as a part of complex therapy in comparison with the standard complex treatment regimen supplemented by dental product containing 1% metronidazole and 0.25% chlorhexidine digluconate, showed a marked improvement in subjective quality of life of patients. Pain during individual oral hygiene and food intake (decrease to 0%, p1 0.05, p2 0.05), a feeling of bursting in the gum (decrease to 0%, p1 0.05, p2 0.05), bad breath (decrease to 0%, p1 0.05, p2 0.05) and bleeding gums (decrease to 0%, p1 0.05, p2 0.05) were completely eliminated. Compared to the control group, OHI-S index of the main group decreased by 79% (from 1.9 to 0.4, p1 0.001, p2 0.001), PI index decreased by 80.6% (from 3.1 to 0.6, p1 0.001, p2 0.001) and SBI index decreased by 100% (from 3 to 0, p1 0.001, p2 0.001). During the course of treatment of patients with chronic generalized catarrhal gingivitis, a decrease in the average values of the PMA index was observed. In the group of patients using hygienic gel as a supplement to treatment, the decrease in this index was 85% (from 651.53 to 100.82%; p1 0.001, p2 0.05), and when using a complex drug containing 1% metronidazole and 0.25% chlorhexidine digluconate, the value of the PMA index decreased by 51% (from 611.17 to 301.4%; p1 0.001), in the control group, the index value decreased by 28% (from 671.67 to 481.26%; p1 0.001). Conclusion. In assessing of the subjective quality of life and index indicators of the periodontal status in the treatment of chronic generalized catarrhal gingivitis, the best results were observed in the group using a dental hygiene gel based on -mangostin [1,3,6-Trihydroxy-7-methoxy-2,8-bis(3-methyl-2-butenyl)-9H-xanthen-9-one], a xanthone from mangosteen fruit, compared with the control group and the group using a complex drug (1% metronidazole and 0.25% chlorhexidine digluconate).