Dermatologists say that old makeup may be containing more than just powder; they could be harbouring dangerous bacteria.
"Most women do have a drawer full of cosmetics that have been partially used," says Angela Bowers, M.D., dermatologist on the medical staff at Baylor Regional Medical Center at Grapevine.
On when to dispose of these old cosmetics she said, "It's difficult to know because cosmetics usually don't include expiration dates."
Experts say that people should go by when they first opened the makeup, in order to determine the expiry date.
Out of the entire cosmetic products, eye make-ups and liquid foundations last the least amount of time and should be thrown after just three months.
"The bacteria can get in there and the preservatives might not be working quite as well as they were when you first opened it. If you get some of that in your eye you may develop conjuctivitus which we know as 'pink-eye,'" explains Dr. Bowers.
Dr. Bowers added that powders and foundations opened more than a year ago can also cause infections.
"Some women may develop a peri-oral dermatitis from using some old, expired makeup that might irritate the skin and cause little red bumps that look like acne," she says.
And its not just makeup, but makeup applicators that should be replaced regularly.
"If you use sponges to apply makeup, you should replace those at least once a week," says Dr. Bowers.
It may be painful for most women to throw away expensive products, but not doing so could hurt worse.
"If you end up in the doctor's office with an infection, all those savings are negated. You always want to have a clean face with some good, fresh product on there," she adds.
Dr. Bowers says that sharing lipsticks is another way by which makeup can cause health problems. Sharing lipsticks, lip glosses or lip balms with someone who may have a strain of the herpes virus could leave you with cold sores of your own, she explains.