Not expired ones. There are many good brands and blends of probiotic cultures that may be recommended by your GI or primary doctor. My patients like the align brand for the gastrointestinal tract. Just don't buy expired probiotics and if they are supposed to be refrigerated, make sure they are.
Discuss with your MD. Be sure to discuss this with the doctor that diagnosed you with small intestinal bacterial overgrowth. A number of antibiotics will work; which one prescribed depends on your history (drug allergies, intolerances) and the specific situation.
Maybe temporary fix. If you have ibs due to sibo (small intestinal bacterial overgrowth)--antibiotics like xifaxan (rifaximin) may help. Sibo may also occur from anatomic variations in the small bowel, altered small bowel motility, or a variety of systemic conditions that prevent permanent cure (e.g. The bacteria just grow back).
How to check for small intestinal bacterial overgrowth means what tests to check you are suffering from them?
See a GI doctor. Intestinal overgrowth syndrome usually occurs only under very circumscribed circumstances with predisposing risk factors. If you have these and are manifesting symptoms of malabsorption you should be seen promptly by a GI doctor.