if you are on the road to being healthy (diet and mentally, good liver function, kidneys, stomach acid, enzymes etc), and you do a de-worm with humaworm, you should be to the point where parasites will NOT be able to survive in your body...as moreless says, a healthy alkaline body will force parasites to leave the body...ANYTHING that is healthy will make it near impossible for parasites, fungi, or bacteria to proliferate period