I think it worked well but I don't know how to tell if they are worm-free...But I will say that after three weeks of giving them this (2 sprays a day in their water bowl) that they are happier, (my one has lost weight) and have lots more energy. One of them did throw up a really scary looking insect-like looking thing and their bowel movements have definitely increased and are healthier looking. It was a good cleanse for them and I am sure it removed at least some stuff. I also gave it to my 2 1/2 year old son (my naturopath said it looked like a good product) for about 10 days. He had been slightly bound up with constipation. It softened his stools in about a day and he was back to 2 bowel movements per day. I also noticed that while taking the remedy that his bowels were bigger, and smellier and different coloured like when we cleanse. I plan on giving them all this again in a few months time. I would recommend trying it. How old is your girl and how do you know that she has parasites?? You can purchase ithe paralixer threw your local health store...Here is the link and good luck!