Coffee does not appear to cause inflammation in most people. Research has generally found either no clear effect on inflammatory markers or an association between regular coffee intake and lower levels of some markers of inflammation.
However, the evidence is not completely consistent. Some studies found lower C-reactive protein, or CRP, and other inflammatory markers among coffee drinkers, while others found no significant overall difference. Randomized studies are limited, so it is not possible to say that coffee reliably reduces inflammation.
Caffeine may also affect people differently from coffee as a whole. Some research found that caffeine or caffeinated coffee increased certain inflammatory markers in specific circumstances, while other studies found similar potentially beneficial associations with both caffeinated and decaffeinated coffee. Individual responses may therefore vary.
Coffee should not be used as a treatment for inflammation or inflammatory disease. Anyone with ongoing pain, swelling, stiffness, fever, or other unexplained symptoms should speak with a primary care doctor or rheumatologist rather than changing coffee intake or taking supplements on their own.