Totally agree that it will take a while for movicol/miralax to be effective. If you have a lot of hard stools there may be quite a build up that needs to be passed and so taking anything that gets the bowel moving may result in some discomfort/nauaea/ stomach cramps to begin with. I was very constipated after an operation and needed to take six sachets on the first day and then 4 on the second day to clear the hard stools and I still may have had the use a glycerine suppository to get things moving to begin with then it was a case of diarrhoea for a couple of days as I reduced the amount to one a day. You also need to drink a lot of water as the movicol makes the bowel take in more water from the body. Now things are better as I just take one sachet a day and it keeps things regular and comfortable!