Make sure everybody washes their hands with soap and hot water after going to the restroom - in the case of pinworms, wash all underclothing and bedsheets in hot water daily - and disinfect the bathroom daily during the cleanse. Parasite eggs are microscopic and many can live without a host for several days or more. These eggs are being removed from the body and you just don't want them hanging around the house waiting for the chance to reinfect you - or your houseguests! (In-laws maybe - houseguests - no. ;)