Very simply, a cruelty-free product is one that does not test its products on animals. Among several manufacturers that have been in the market for many years, Revlon and Avon have adopted cruelty-free practices and therefore, one way to show your support against animal cruelty is to purchase these products and boycott those companies that still follow this practice.
While drugs are required by Federal Law to be tested on animals (which is a reality that we have to accept), there is no such mandate when it comes to cosmetics or even household products. And since research and development have shown several substances used in cosmetics to be safe, there should be no reason why these items still need to use animals for testing anymore.
At another level altogether, there are companies that might be cruelty-free but their products contain animal ingredients, and this is one of the gray areas that one might keep in mind. Yet another tricky issue comes in the form where the supplier might have tested the ingredients on animals while the manufacturer continues to be cruelty-free.
And finally, if a cruelty-free company is bought over by one which still tests on animals, this can also cause doubt in the minds of the people who have to make a choice between choosing cruelty-free products.
All in all, it is important that you do support cruelty-free products but you should make your decision once you have truly confirmed whether or not the manufacturer is indeed, cruelty-free, as mentioned in the aforementioned cases.