10. Bloodletting
For centuries, people felt that certain sicknesses were a result of liquid balance somehow being thrown off. Thus, removing blood was meant to bring balance. It’s widely believed that it worked in cases of things like Hypertension, which could happen with quite a number of illnesses. However, beyond this, there wasn’t much use in it.
As one of the major ancient medical practices, it remained common until the 18th Century in Europe. Today, we still do this but not always in the exact form. When we’re sick, our doctor may want to take our blood and see if there is an issue with it. Hence, modern bloodletting is basically getting blood drawn as well as donating our blood for others.