what is a cholagogue
A cholagogue is a medicinal agent which promotes the discharge of bile from the system, purging it downward. In Patrick O'Brian's Post Captain (Ch. 10), which is set in the Napoleonic era, Stephen Maturin, one of the book's main characters (who is also a physician, naturalist and spy) sits in the snug of the Rose and Crown in Deal, Kent, and drinks a good tea described as an unrivalled cholagogue.