Hippocrates, known as the father of western medicine, purportedly believed that the four humours that governed human health were: blood, phlegm, black bile, yellow bile, whereas Galen of Pergamum (129–216 AD) believed that blood was the predominant humour. An imbalance between these humours was believed by both to be responsible for human disease. Galen’s philosophy held sway for 1500 years and encouraged the intervention of bloodletting as a treatment for many diseases, what is more is that this therapeutic intervention continued for many decades after its benefit had been widely discredited.
