Objective: The objective of this research was to evaluate the effects of bromelain (derived from Ananas comosus) upon periodontitis in rats. Materials and Methods: Twenty-four rats were separated into groups: control, periodontitis, and bromelain treatment. Bromelain was administered daily by intraperitoneal injection for 20 days. Periodontitis was induced by ligature around the first molars. Oral parameters and blood biomarkers were measured. The histopathological evaluation of the hepatic tissue was performed. Bromelain treatment significantly reduced several oral inflammatory parameters, alveolar bone loss, and blood biomarkers compared to the rats on periodontitis. Results: Treatment with bromelain improved the steatosis score. Bromelain used in ligature-induced periodontitis in rats was able to reduce the oral inflammatory parameters Gingival Bleeding Index (GBI), tooth mobility (TM), probing pocket depth (PPD), malondialdehyde (MDA), alveolar bone height (ABH) and gingival myeloperoxidase (MPO) and blood parameters (cholesterol, triglycerides, alanine aminotransferase, and aspartate aminotransferase). Bromelain treatment reduced the impact of periodontitis, such as the reduction of hepatic steatosis and improvement in the dosages of MDA and GSH. Conclusion: Bromelain acts as a potential adjunct in the non-surgical treatment of periodontitis and, consequently, reduces the impact of periodontitis, acting as antiinflammatory and antioxidant. K E Y W O R D S alveolar bone loss, anti-inflammatory, antioxidant, periodontal diseases, proteinase How to cite this article: Alves EHP, Carvalho ADS, Silva FRP, et al. Bromelain reduces the non-alcoholic fatty liver disease and periodontal damages caused by ligature-induced periodontitis.