Study aim: The effect of curcumin-piperine supplementation on inflammatory factors and clinical signs in patients with rheumatoid arthritis Design: This study is a clinical trial with a control and randomized parallel double-blind group, in which 54 patients with rheumatoid arthritis will be divided into two groups receiving curcumin-piperine supplement (n = 27) and placebo (n = 27). Settings and conduct: In this study, people with rheumatoid arthritis will be admitted to Al-Zahra Hospital. Random allocation will be done using a random number table. Entry of individuals and assignment of each person to one of the two groups will be done by the relevant specialist. Curcumin-piperine supplement and placebo will be packaged in similar boxes and the researcher and patients will not be informed of the contents of the packages until the end of the study. Participants/Inclusion and exclusion criteria: Inclusion criteria: Willingness to participate in the study, age 30-70 years, completing informed consent.Rheumatoid arthritis According to the rheumatologist Inclusion criteria: Pregnancy and lactation Smoking Underlying diseases, weight loss and bariatric surgery in a recent years, lack of special diet and herbal supplements Intervention groups: 1) Intervention group (n = 27) daily one capsule containing curcumin piperine (containing 500 mg of curcumin extract and 5 mg of piperine 2) control group (n = 27) daily placebo capsule (505 mg of maltodextrin) with diet and activity recommendations. Main outcome variables: Clinical signs, inflammation indices such as quantitative CRP and ESR, and oxidative stress factors such as Total antioxidant capacity (TAC), Superoxide dismutase (SOD), Malondialdehyde (MDA), Rheumatoid factor (RF)