Is it legal  to sell licensed products on eBay?

Question Details:

Is it illegal to sell shampoo on eBay? These are brands usually sold through authorized salons and can only be bought with a cosmetology license issued through the state. My mother-in-law has the license and we have been selling on ebay for a small profit. I was told this was illegal and we can be sued. Does anyone know the laws on this? Important Notice