Colds can be categorized into wind-heat and wind-cold. Chinese medicine believes that there is phlegm, which is produced when the body’s essence receives heat or cold stimulation. If it is stimulated by heat, the cause is similar to porridge, if the fire is very big, it will turn yellow, if the fire is very good then it is white phlegm, which shows that wind-heat colds should be yellow phlegm, while wind-cold colds should be white phlegm. Chinese medicine takes analogies to illustrate that yellow color represents the burning of something due to too much fire, while white color is cold or no fire, then it is white phlegm.