What can cause ibd flare ups?

Good question: Stress involved but not causative. Not sticking to meds is a big cause. Crohn's patients must not smoke-definite cause of flates. Nsaid type drugs, e.g. Advil/nuprin (ibuprofen), naproxyn (aleve), even Aspirin can cause flares. Other (unknown) factors. Associated with high fat, especially land fat (omega 6) intake, less so with lower fat and marine fat (omega 3).

Multiple causes: One causes that need to be rule out in case of flare ups are infections of colon especially c.Diff colitis and bacterial infections which can be checked by doing stool test.Other factors are including no compliant with medications, stress, dietary and taking Aspirin or nsaids such as motrin, aleve (naproxen) or other similar meds.