What is the black bile?

Black bile is one of the four humors in ancient and medieval medicine, alongside blood, phlegm, and yellow bile. It was believed to be produced by the spleen and was associated with the melancholic temperament, which was characterized by sadness and introspection. The concept of black bile originated from the teachings of Hippocrates and Galen, and while it is no longer recognized in modern medicine, it played a significant role in the historical understanding of health and disease.