If you had assumed that the theory of ‘humours’ had been unanimously relegated to the ‘didn’t work’ shelf of ancient philosophy, then… perhaps you’d be wrong. It appears that Hippocrates’ concept of a four chemical system that affect behavior is enjoying a bit of a revival.  […]

Source:  https://classicalwisdom.com/science/medicine/the-humours-of-hippocrates-which-one-are-you/