It's probably that you're not understanding what you have to do to get rid of the parasites. Humaworm has some good products. I've used them, but you need a foundation in understanding why you think you failed. You haven't failed, you just need to go a little further in your quest to get rid of the parasites and understand what happens when you also clean out poisons that cause you to have parasites in the beginning. The poisons have to be cleaned out as well as the parasites killed so you can be successful.