Updated project metadata. The joint disease rheumatoid arthritis (RA) is characterized by persistent synovitis, leading to cartilage damage, bone erosion, and ultimately impaired joint function. The disease affects 0.5 to 1.0% of adults in developed countries, and is three times more frequent in women than in men. A number of autoantibodies can be detected in RA patient’s serum targeting the patient’s own proteins. Several of these proteins, including rheumatoid factor, can also be detected in patients suffering from other autoimmune diseases, including the inflammatory bowel diseases (IBD). IBD and RA share several genetic risk logi, an altered gut microbiota, and environmental risk factors. Articular involvement is the most common extra-intestinal manifestation in patients diagnosed with IBD, with a prevalence between 17 to 39%. Additionally, methotrexate (MTX) is the most frequently prescribed immunosuppressive drug for RA and the second most for the IBD, indicating close similarities between the two diseases. We, therefore, characterized the protein content (the proteome) of the colon mucosa of gastrointestinal healthy RA patients, to investigate if we could detect IBD-related changes. The LC-MS/MS analysis was conducted as part of a previous study (ProteomeXChange submission PXD001608), enabling a comparison between the two datasets, containing the colon mucosal proteome of 11 RA patients, 10 IBD (ulcerative colitis) patients, and 10 controls. This data submission covers the triplicate proteome analysis of the colon mucosa of 11 gastrointestinal healthy RA patients.