From the perspective of Chinese medicine and nutrition, watermelon generally does not cause fire, fire may be related to diet, lifestyle habits, climate change and other reasons. “Fire” is a folk saying. Chinese medicine nutritional point of view, often eat spicy stimulation, warm, greasy, fried and other foods easy to fire. Usually referred to as “on fire” is generally relatively light, mostly belongs to the Chinese medicine heat evidence of mild symptoms, such as not accompanied by systemic heat symptoms of red eyes, corners of the mouth vesicles, yellow urine, toothache, sore throat and so on. Watermelon is cold in nature, sweet in taste, has the effect of clearing heat and removing vexation, relieving summer heat and generating fluids, and diuretic, and can be used to relieve thirst and vexation caused by summer heat (irritability and sultriness), short and red urination (urine is small in quantity and dark yellow in color); and mouth sores caused by inflammation of the heart. Watermelon is a cold food and does not normally cause fire. Fire may be related to other causes, such as eating too much spicy and stimulating food; smoking, drinking, staying up all night and other bad habits; emotional fluctuations, irritability, anxiety and other emotional factors; external wind heat and other evils may cause fire. Specific causes and diagnosis and treatment, need to be completed under the guidance of a professional doctor, the emergence of more serious symptoms of fire should be timely medical care.