Fibre aids with D or C...fibre is your friend, it helps sweep the bowels of bad bacteria, it firms stools up yet helps them go through the GI tract with ease, and it can even cut back daily BM's (as it has with me) we are desginged to eat fibre, our bodies need it. Only those with stricturing/blockage issues should be more cautious, a fibre supplement would be more beneficial for those stricturing/blockage patients.
You always start with a small amount and slowly increase (if necessary) once your system has adjusted to it, part of the adjustment included gas/bloating which is normal, it happens to healthy people too. If you stick with it daily then your system can adjust to it, and drinking plenty of water daily is necessary as well.
My GI told me to start using fibre supplements daily and indefinitely, it's been almost 6 yrs later and I'm glad I listend to him...I can now tolerate eating ALL fibreous foods without getting all gassy/bloated, popcorn, all nuts/seeds, fruits and veggies....I was in a terrible flare at the time he told me to start taking them and I'm glad I did, it was worth the extra 3 months of having increased gas/bloating cuz after 3 months, no more bloating at all and very minimal gas. I was also bleeding at the time I started with them, best advice I ever got from a GI.
:)