How to make my cousin stop eating things?

Okay, my 2 years old cousin eats everything! everytime i take her to get new clothes i go by the make-up section and she opens packets of make-up and starts eating it. When i give her baths she eats the soap and shampoo. When i take her to the park to play she eats the sand and gr. I told her numerous times that ur not suppose to eat that kinda stuff, but she doesnt listen and she has an infection from eating dirt. Oh, and when she uses the potty she eats *cough* im afraid she's gonna get severly sick. What should i do? oh and btw her mum and dad r dead so im like her mum.