Bile occupies a peculiarly liminal position in the depth-psychological corpus: it is simultaneously a physiological substance, a cosmological principle of corruption and dissolution, a humoral determinant of temperament, and an alchemical impurity awaiting purification. Plato’s Timaeus furnishes the foundational medical ontology, presenting bile as old, decomposed blood that re-enters circulation as a corrosive agent capable, in sufficient quantity, of burning through the body’s very moorings and liberating the soul from the marrow. Commentators on the Timaeus elaborate a taxonomy of bile by colour—yellow, black, and a further ‘bilious’ variant—each corresponding to progressive stages of putrefaction. The humoral tradition, transmitted through Jonson and summarized by Place, assigns yellow bile to fire and choleric vindictiveness, black bile to earth and melancholy—etymologically melan-chole, ‘black bile’—thereby furnishing depth psychology with its persistent link between humoral physiology and psychological typology. Onians situates bile within the archaic Greek topology of the liver as the seat of deep emotion, noting that the liver secretes bile while functioning as the body’s principal blood-gland; anger, lust, and fear are felt there. McGilchrist presses this further, asking whether the medieval association of black bile, the spleen, and the left side of the body may illuminate hemispheric asymmetries. Hillman, working alchemically, reads the choleric humor’s yellowing as citrinitas—the intellectually fervent, emotionally saturated stage preparatory to rubedo. Across these registers, bile marks the dangerous boundary between nourishment and poison, health and dissolution.