I have periods of severe constipation; one to two week intervals. I use generic Miralax and it seems to have stopped working. Now I have intervened with a laxative, Sinnes-S, The first dose of 2 worked fine, but very little results since then. It is said that I have Irratible Bowel Syndrome, and have for years. I also use prune juice, milk of magnesia and apples. Have been to a gastroentologist , and the last colonoscopy was four years ago. That was good with no polops. I am distressed that I can have good, timely bowel movements for quite some time and then drop down to near zero B/M s. Thanks for your help.P. S. I do drink quite a bit of water, daily. Ironically, after I eat dinner and brush my teeth, the brushing process can be a stimulant with, usually, moderate results. But, even that has ceased now.