I have IBS-C as well. I think I've tried everything under the sun to get things moving regularly. Some things have worked for a week or two, but then stop working. I tried Miralax on four separate occasions and reacted very negatively all four times -- so I won't use it ever again. I discovered that my IBS-C is eased significantly when I use unrefined gray sea salt (sparingly) on my food and drink coconut water. Sounds odd, but the minerals from the unrefined sea salt and the fiber, electrolytes, and potassium from the coconut water balance things out and I don't have constipation any longer. I also drink a lot of water through out the day. I'd had constipation for 40 years and IBS-C for 26 years.