Fig.2. Salivary cortisol concentrations (ng/ml) in patients with IBS and controls on the stress day. There were no significant differences in the group means for any measurement period, in the between-group change scores (pre- vs. poststress), or in the within-group difference scores comparing the rest and the stress day. Time points 1 and 2 are preprandial; 3 to 5 are postprandial.