10 beauty treatments that were once popular but are actually incredibly dangerous

• Cosmetics used to contain arsenic, mercury, and radioactivity — all of which can be deadly.
• People used to swallow tape worms to lose weight and wear tight corsets that caused deformities.
• Eyelashes used to be sewn into the eyelids with a needle.

Like clothing and hairstyles, beauty trends come and go. One minute it's achieving glowing glass skin, the next it's coating your tongue in glitter. 

But just because a beauty trend is popular doesn't mean it's safe. Throughout history, people have ingested harmful substances and undergone dangerous, painful procedures in the hopes of attaining perfection.

Here are 10 beauty treatments that definitely needed to go out of style.

In the Middle Ages, women would bleed themselves in order to look pale.

In the Middle Ages, pale skin was considered beautiful because it indicated that a woman was wealthy and didn't need to work outside. To achieve this translucent look, some women bled themselves, according to the book "Introduction to Cosmetic Formulation and Technology."

Bloodletting was also thought to treat physical ailments. While the practice may actually turn out to have some health benefits, it's definitely not for cosmetic use.

Makeup laced with lead caused the death of the Countess of Coventry in 1760.

Lead poisoning was common in the 18th century due to the popularity of lead cosmetics, according to the Museums and Collections department at University College London.

Maria Gunning, Countess of Coventry, used a white lead compound known as ceruse to powder her skin. It was also used to powder hairstyles. She contracted lead poisoning and died at the age of 27. 

"Safe arsenic complexion wafers" were anything but safe.

Arsenic was known to be dangerous and addictive in the Victorian Era, but small amounts in the form of edible wafers were thought to not only be safe but to help one achieve that sought-after pale complexion, giving the skin an "indescribable brilliancy" according to advertisements.

Arsenic is a carcinogen that is "extremely poisonous to humans," according to Healthline.