The gallbladder is a small organ nestled under the liver. It acts as a bag to store and concentrate bile, a dark green to yellowish brown fluid produced by the liver. Bile flows from the gallbladder into the small intestine where it breaks up fats into droplets for better absorption.
The gallbladder is not very humorous, but from ancient Greek times and well into the 19th century yellow bile was considered one of the four humors that kept the human body in balance. The four humors were blood, phlegm, black bile and yellow bile, all linked to the four elements: air, water, earth and fire. Blood and phlegm being moist were considered the agents of air and water, respectively. Black bile was the dry melancholy humor and represented the Earth. Yellow bile was also a dry humor, but choleric and connected to fire. Hippocrates identified and wrote about these four bodily fluids. It was Galen who later theorized that humors were formed in the body rather than ingested. He thought warm foods tended to produce yellow bile, while cold foods produced phlegm. While today we might chuckle at the theory of the humors suggested by great thinkers like Galen, he did get some things right, such as recognizing that the liver and the gallbladder are the keys to bile production.