Diagram showing the 4 humors or body fluids as understood by ancient physicians Humorism, or humoralism, was a system of medicine about the makeup and workings of the human body. It was a belief that too much or too little of any of four distinct body fluids in a person directly influenced their temperament and health. The humoralist system of medicine is highly individualistic. Each individual patient was made up of their own unique combination of humors.