Chinese medicine determines cold and heat mainly based on the analogy of nature. Yellow phlegm from a cough is a wind-heat cold, like porridge boiled in a pot, which becomes yellow or even mushy after being dried up by the fire, so Chinese medicine defines yellow phlegm as a wind-heat cough. In addition, you can also eat Leyang pear stew with rock sugar, fishy grass with cold vegetables, and dandelion with cold vegetables.