What practice involves draining a quantity of blood to cure illness or disease?

The practice known as bloodletting involves the intentional draining of a certain amount of blood from a person as a means of treating various illnesses or ailments. Historically, it was believed that many diseases were caused by imbalances within the body, often thought to involve an excess of blood. By removing this blood, practitioners aimed to restore a balance, alleviating conditions such as fever or inflammation. This practice was common in various cultures and was prevalent from ancient times until the 19th century.

While phlebotomy refers to the act of making an incision in a vein to draw blood, it is typically performed for diagnostic purposes or blood donation rather than for therapeutic bloodletting. Venesection is a term sometimes used interchangeably with phlebotomy, but it can also refer specifically to the process of withdrawing blood from a vein for the same purposes. Hemotherapy involves using the immune components of blood, such as in blood transfusions, and is not related to the archaic conception of draining blood to cure diseases. Thus, the primary focus of bloodletting as a therapeutic practice makes it the correct choice in this context.