Objective: Quercetin is a flavonoid with anti-inflammatory properties and is used in a few rheumatic conditions. Herein, the authors review the rheumatological diseases in which quercetin has been investigated: rheumatoid arthritis, osteoarthritis, gout, and pre-hyperuricemia.

Materials and Methods: A systematic search of articles published in PubMed/MEDLINE, Web of Sciences, LILACS, and Scielo from 1966 to August 2022 was done. No language restriction was used. The reference lists in the selected articles were analyzed to identify other publications.

Results: There are only 6 articles published in this field, involving a total of 284 patients. Rheumatoid arthritis was the most studied disease (n=3 articles), and then osteoarthritis (n=2), gout (n=1), and pre-hyperuricemic subjects (n=1). Age varied from 19 to 62.5 years old; females predominated, ranging from 83% to 100% in most studies. However, all participants were male in the two articles in which gout and pre-hyperuricemia were evaluated. Disease duration varied from 5.0 to 10 years. Quercetin dosage ranged from 45 mg to 2000 mg/day. Regarding outcome, all studies except one showed a good result after quercetin treatment, with improved pain, morning stiffness, disease activity score-28 joints (DAS28), uric acid, inflammatory biomarkers, and other parameters in the studied diseases.

Conclusions: This review shows that quercetin use in some rheumatic diseases has good effects, although new studies to confirm these findings are needed.