Wondering how you got that rash on your face? Your expired makeup can possibly be the reason behind your unfortunate skin problems. According to a recent study by London Metropolitan University scientists, expired cosmetics actually carry more bacteria than you probably imagined. To be more exact, old makeup products tend to contain ubacterium, aeromonas, and propionibacterium, which can lead to health issues including bacterial vaginosis, gastroenteritis, wound infections, acne, and other skin conditions. While expired concealers and foundation can cause facial blisters or rashes, old mascaras can trigger problems such as pink eye.

To prevent yourself from falling victim to serious health problems, check out the guide below to learn about the average life expectancy of various makeup products:

Mascara: 3 months
Liquid eyeliner: 3 months
Pencil or Kohl eyeliner: 12 months
Cream blush and multiple sticks: 12 months
Liquid Foundation/Concealer:  12 – 18 months (a water-based foundation will last up to 12 months, while oil-based will last slightly longer – 18 months – due to its natural preservative system)
Lipstick: 12 – 18 months
Powders (blush, bronzer, foundation):  24 months
Eyeshadow: 24 months
Nail polish: 24 months
Fragrance:  3 – 5 years