My intestinal problems were so severe I, and my gastroenterologist, thought I had celiac disease. I tested negatively, blood and endoscopy, and have since resumed eating gluten-rich foods without complications. However, what we did find was that vitamin supplementation was necessary to overcome years of diarrhea from lactose intolerance, which basically strips the gut of flora over time. But, the vitamins were not the flora fix, rather they fixed the health issues with skin and other parts of my body. The fix to the intestines came after a couple months on probiotics. Specifically, they contain 10 varieties of bacteria with approx 20 billion cells as my daily intake. All cramping, constipation/diarrhea, backups and frequent urges are gone. I can eat out without an immediate need to use a restroom after the meal. I no longer get diarrhea (except heavy dairy without an enzyme at mealtime) and I have regular movements without strain or pain.
My point is that the probiotics can make a huge difference if flora is the issue. However, they need to be strong enough and contain the right mix of strains for your needs. Many probiotics sold in stores are weak and of one or two strains, which may or may not be the ones you need. Even with 10 or more you may still have a deficiency that is not covered. The only way to know is to use them, most likely for a couple months, and if that works then continue it indefinitely. Probiotics cause no harm if you have no noticeable side effects and they have great positive effects for those who need them. Talk to your gastro...he/she may recommend one that will fit your needs. Nothing lost in trying them besides the money they cost to buy.