Miralax has not caused too many problems like diarrhea unless I ate a lot of cooked spinach or greens. My urology doctor (she is the head of the urology department at Baptist Hospital in Winston Salem, NC) had me start on just a little bit of Miralax and a serving of oatmeal to add bulk (Metamucil gives me gas). Add a little bit of Miralax until you find the right balance. I do use an extra dose if I have some cheese or chocolate which constipates me. Hope this helps.