上火 is a uniquely Chinese concept rooted in traditional Chinese medicine (
中医). There's no direct English equivalent — it covers symptoms like sore throat, mouth ulcers, acne, and nosebleeds, all attributed to excess 'heat' in the body. Almost every Chinese person believes in it, and brands like
王老吉 herbal tea are marketed specifically as
怕上火，
喝王老吉 ('Scared of getting hot? Drink Wanglaoji').
