Recent research has increasingly shown that depending on the foods we eat, gut flora may be affected by an inflammatory or anti-inflammatory response, thus playing an important role in inflammatory autoimmune diseases, such as rheumatoid arthritis or gastroenterological disorders. Gluten seems to be a glycoprotein with a clinically relevant inflammatory effect. Several observational studies and anecdotal cases reported a correlation between gluten and various diseases, including autoimmune diseases, such as rheumatoid arthritis. This study aimed to evaluate whether gluten-free diet could be effective in controlling inflammation and ongoing rheumatoid arthritis symptoms. We report 4 cases of patients with long-standing rheumatoid arthritis with no response to several conventional and biotechnological drugs, treated with a gluten-free diet concurrently with the drug therapy. Our patients presented different degrees of response to the diet, in terms of disease remission and improvement of symptoms. Our cases confirm that a gluten-free diet may improve symptoms of rheumatoid arthritis, even in patients resistant to conventional drug therapies.