I have heard some information about stubborn parasites. First of all, it is lingering egg sacs that can cause continuous cycles in your body. So a cleansing program should be uniquley tailored for you and the very end should include an enema of a special tincture to kill the final sacs. However, before that final stage, you must cleanse and rid your body of what ever you have. I read a bout a doctor's friend who was 33 yrs old and passed a huge worm after the third month of cleansing. That is 90 days of cleansing!! Somepeople only cleanse for a day, a few weeks, etc. And this individual needed that third month. Lastly, it would also depend on the cleanse your using and how potent it is. Hmm. Best wishes to you as you cleanse. I think everyone needs to deworm, but only some of us know it.