Since the body usually raises temperature in its wisdom to heal itself of foreign invaders. I would think that hot water is much better for ridding parasites than cold water. I also read in a article that hot water is better against them but I can't remember where. I read so many articles on health, it's hard to keep track. But that's why I avoid the hot and cold water treatment that some say is good for circulation etc... I will only use hot water till I know I'm good to go-no more parasites. Oh but we do have a shower filter to avoid the flouide, chlorine etc...