Ingredient labeling in the food industry has become the standard, as customers have demanded to know what they are eating.  Now, similar calls are being made in the cosmetics industry, with customers demanding to what they are putting on their skin.

"I think people are becoming more aware and that's a good thing.  The cosmetics industry has not been that forthcoming for a lot of reasons.  One is patents.  Everyone has a secret ingredient that makes their product better," says Dr. Mark Nestor of Skin and Cancer Associates.

For one group, the need for an ingredients list on cosmetic labels is particularly important.  More than two million people suffer from Celiac Disease, a painful digestive condition that is caused by sensitivity to gluten.  People with disease cannot eat foods containing gluten, and many do not want it on their skin either.

"If somebody has a severe sensitivity and there is gluten in lipstick, which to some degree is getting ingested, or toothpaste...sure that makes some sense," says Dr. Nestor.

He also says there are other ingredients that can cause rashes, like formaldehyde, silicone, and parabens. 

Older products can also cause skin sensitivity.  Experts recommend throwing out cosmetic products after a year.

Experts also warn that products that say they are "all-natural" are not necessarily better.  Many natural ingredients include menthol and eucalyptus, which can cause skin irritation and sensitivity.