上火 ("rising fire") is the classic TCM concept of having too much internal heat - symptoms include sore throat, mouth ulcers, acne, and constipation.
降火 is the cure: drink
凉茶 (cooling herbal tea like Wong Lo Kat
王老吉), eat
苦瓜 (bitter melon), or
绿豆汤 (mung bean soup). It's everyday cultural common sense across Chinese-speaking communities - even people who reject TCM in general use these terms.
