I've just being diagnozed with a Urinary Tract Infection and have been put on Bactrim for ten days. I'm IBS, very, very constipated type and am finding this antibiotic is making things so much worse and even with laxatives I'm still extremely constipated. Is there anything I can do to counteract this effect? I have always found antibiotics constipating and that's how my IBS began.Not sure what to do. I really thought I couldnt get much more constipated until I started on Bactrim.Anyone else been through the same issues with antibiotics?? I wish I would get some kind of diarrhea for once in my life.