Hello - HCL (food grade) is included in many food additives. In the body it "sterilizes" the stomach and helps prevent bacterial and fungal overgrowths - such as candida - in the digestive system. It will help with this type of parasite, but it alone will not get them all. I know that long term use has no ill effects on the body. Maybe parasite cleanse twice per year and HCL in between cleanses would be a good battle plan. Thanks!