19 patients with CFS/FM, 16 patients with rheumatoid arthritis (RA) and 18 sedentary controls participated in a double-blind crossover trial of a single dose (1 g) of acetaminophen with tests of pressure pain threshold before and after treatment. The group of Belgian researchers led by Dr. Mira Meeus report, “CFS/FM patients present more central pain processing abnormalities than RA patients; acetaminophen may have a limited positive effect on central pain inhibition, but other contributors have to be identified and evaluated.” (Pain Physician, Mar. 13, 2013)