THE INCIDENCE of inflammatory bowel disease (IBD) is in- creasing worldwide. The underlying causes of IBD, which encom- passes Crohn's disease and ulcerative coLitis, are unknown but are thought to be a com- bination of genetics, environmental factors, abnormal immune re- sponses and disruption to the microbiota in the gut. IBD can be a devas- tating disease, affect- ing quality of Life and increasing risks for bowel cancer. Effec- tive management has been an elusive goal, but with better under- standing of the inflam- matory and immune pathways involved in IBD, more successful therapies are entering clinical practice. To deliver quality care and help people with IBD manage this dis- ease, nurses must be familiar with the cur- rent understanding of its causes.