What were the four humours are?

The four humours are ancient Greek medical concepts that explain human health and temperament, consisting of blood, phlegm, black bile, and yellow bile. Each humour is associated with specific characteristics: blood is linked to a sanguine temperament (sociable and carefree), phlegm to a phlegmatic temperament (calm and reliable), black bile to a melancholic temperament (thoughtful and reserved), and yellow bile to a choleric temperament (ambitious and leader-like). Imbalances among these humours were believed to affect both physical health and personality. This theory was influential in ancient and medieval medicine before being replaced by modern medical understanding.