This part of a series of posts, with the same rider: this is published here because of our interest in ancient greek medical theory.  We do not necessarily endorse the ideas. The “Unani” part of Unani Tibb Medicine, that is, the elements from Greek medicine that the Islamic doctors adopted as part of Islamic medicine, does give some background to the theories that held sway with, for example, Ibn Sina.

Greek Medicine from Hippocrates to Galen: Studies in Ancient Medicine Edited by John Scarborough Philip J. van der Eijk Ann Ellis Hanson Joseph Ziegler write, 

“The humours also determine the customs of the soul.

  1. Blood makes the soul more joyous.

  2. Yellow bile makes the soul quicker-tempered, bolder or more impudent, or both.

  3. Phlegm makes the soul lazier and more foolish.

  4. Black bile makes the soul quicker-tempered and cheekier.”