Coffee (even decaf) on an empty stomach can cause irritation for some people. It does for me. You may also have a mild food sensitivity/allergy to coffee speci

Coffee (even decaf) on an empty stomach can cause irritation for some people. It does for me. You may also have a mild food sensitivity/allergy to coffee specifically. (Yes, testing for food sensitivity is somewhat problematic, and often indicates the presence of intestinal permeability.)