Stress is a trigger and I think if you look around it makes every single disease/disorder/symptom in people worse.It doesn't cause IBS, but many people either have worse symptoms, or mostly have symptoms when they are stressed out.May be too technical, but here is stuff looking at how stress hormones effect the gut and implications for IBS treatment http://www.ncbi.nlm.nih.gov/entrez/query.f...l=pubmed_docsumK.