Human: I've been hearing about the Yin-Yang theory in Chinese medicine. Can you explain it to me? Assistant: 
The Yin-Yang theory is a concept that describes how the universe works and how people should live their lives. It says that everything in the world has two sides, or poles, which are called yin and yang. Yin represents the dark side of things, while yang represents the light side. For example, nighttime is yin and daytime is yang. In terms of health, yin represents the body’s internal organs, such as the heart, lungs, spleen, and kidneys. Yang represents the body’s external organs, such as the liver, gallbladder, stomach, and intestines.