Figure 1 Intestinal permeability in healthy controls, in patients with Crohn's disease (CD), their first degree relatives (CD‐R), and in non‐blood relatives (CD‐NR) (median (interquartile range: 25th–75th percentile)) . Intestinal permeability was increased in CD and CD‐R compared with controls. PI, permeability index (lactulose (Lac)/mannitol (Man) ratio). p<0.004 compared with: **controls, ††CD, ‡‡CD‐R (Mann‐Whitney test). Bordered area range of normal permeability.