Chronic periodontitis (CP) is the most common periodontal pathology, which leads to dysfunction of the dental system. 52 patients with CP were examined. Each person assessed the condition of their periodontal tissues using the following indices: PMA, API, SBI. To study hypoxia, the functional activity of erythrocytes was examined using spectroscopy. It was found that changes in periodontal tissues in chronic periodontal disease are accompanied by the development of hypoxia, which requires suppression and correction of the functional activity of erythrocytes.