These makeup samples may make you feel prettier — but they may also make you sick.

Makeup testers in cosmetic stores, including lipstick, mascara, eye shadow and blush, were found to potentially carry deadly illnesses and sexually transmitted diseases, according to an investigation by Charlotte broadcaster WCNC.

The news station swabbed 10 makeup testers from area cosmetic stores. The swabs were then placed in petri dishes of agar — a substance used to reveal any organisms hidden in the sample. The team waited five days and took the dishes to an infectious-disease specialist. The results were revolting.

“Some of these are molds,” says Dr. Arash Poursina of the Piedmont Medical Center, examining photos of the dishes and identifying what could be E. coli, herpes, staph and MRSA. The last two are potentially deadly, if they get into your bloodstream, Poursina says. And herpes has no cure.

“Even sexually transmitted diseases can be transmitted by sharing makeup,” Poursina says.

The eye shadow and lipstick proved to be the grossest of the samplers, but Poursina recommends against touching any makeup samples.

In contrast, when WCNC reporters swabbed just-opened makeup samples, the products contained no bacteria colonies.

The takeaway, Poursina says, is to avoid the testers at all costs, “unless you were the very first customer and they have just opened up a brand-new sample,” he said. Even using new swabs or cotton pads is risky.

Experts have long warned about the dangers of using old makeup as well. A woman from Australia once learned that lesson the hard way when she wore 20-year-old eye makeup and went blind.