Natural dog flea spray also works on lice  

We have problems with allergies, etc. around here, so when we have a flea problem with our 3 little dogs, I vacuum every day, empty into the outside trash can and wash the dirt bin, then sprinkle the carpets and furniture with table salt. It takes work but very little money, and there are no residual effects.
And when my grandkids had headlice, we slathered their heads with mayonaise, let it sit for 30 minutes, then rinsed. We then used the tiny metal lice comb to remove the varmits and the eggs, then shampooed the hair again. I used the chemical shampoo 3 times when they finally got to me... my hair was down past my waist, and the only thing that finally got rid of them was the above method.
When it comes to these evil critters, whatever works is a good thing!

I use frontline on all of my fur babies because it works great on killing and repleling fleas and ticks. I wouldn't use anything else for there's nothing wrong with it and does so much good. Now I have a hint of advice for your niece, put her bed pillow in the dryer on high for 20 minutes and that'll kill all the lice that's in there.

Tell us more about where this product comes from and what it is cslled. I have one for cats, but have not used it much this winter. Another lice treatment is multi step, but it prevents re infestation, and it is to be used on people. Use either olive oil or real mayonnaise. Work it into hair, all the way to the roots. Leave a shower cap on for two hours. Comb through with a nit comb, then shower as usual. Put on conditioner, leave it, use lice nit comb again. Rinse out remaining conditioner. Condition and comb out thoroughly every night for two weeks and the kid will no longer be getting reinfested, and will also have soft, tangle free hair.