A widely-used Chinese term, literally translated in English as "hot air", is used to describe the idea of a state of "unhealthiness", when one's urine is very yellow, has an odor, or if they eat too much junk and processed food which is a common excuse for nosebleeds, oily skin, and a sense of unwellness.
Heat Evil is caused from drinking large amounts of liquids that contain water, but is not purely water, such as soda and juices. Most of the time, urine that is yellow and has odor is caused by the lack of intake of water.
Person 1: Oh dear, my urine is really yellow, it looks almost like apple juice.. yuck!
Person 2: You probably have heat evil, especially if it smells bad. Try to stop eating unhealthy foods for a while and drink more water.