The Dannon variety of Oikos (Stonyfield makes Oikos as well) has a bunch of thickeners and additives which might be upsetting you if that's what you have. But honestly my guess is that you're flaring, yogurt or not.
dx'ed UC pancolitis 5/12 w/ moderate-severe inflammation
past meds: asacol hd, VSL#3, apriso, rowasa, xifaxan, 6mp, cortifoam, pentasa, cimzia, canasa, butyrate, flagyl, cipro, prednisone, remicade, methotrexate, cholestyramine, cortenema
current meds: canasa, no more steroids!
step one: colectomy w/ end ileostomy, 1/16/13
so much happier already!