Causes of IBD

The exact cause of IBD is unknown. Genetic, environmental, and immune influences, and changes in gut flora (microbiota) have been implicated. It is believed that IBD results from an inappropriate immune response to symbiotic microorganisms in genetically susceptible individuals.


  • Genetic predisposition, meaning that in your genetic profile there is a predisposition for IBD. Having this predisposition does not guarantee the development of IBD, it just makes you more susceptible.
  • Immune influences, an immune system component where the immune system mistakenly attacks the body – in this case the GI tract.
  • Gut microflora, the environment of your gut also plays a role. This means the kinds and number of bacteria in your gut. At the center of the inflammatory process in IBD is “dysbiosis”, which a fancy word for an imbalance of the gut microbiome, which may be driven by host genetics and environmental factors like diet.


It is a combination of these three factors that doctors believe cause IBD.


Source: Hold GL, et al. Role of the gut microbiota in inflammatory bowel disease pathogenesis: what have we learnt in the past 10 years? WJG 2014’20:1192-1210.]