‘蛇蝎心肠’ (shé xiē xīn cháng) is a vivid, four-character idiom that literally means ‘a heart and intestines like those of a snake and scorpion.’ In Chinese culture, snakes and scorpions symbolize hidden danger, treachery, and venomous cruelty—so the phrase describes someone whose inner nature is profoundly malicious, deceitful, and ruthlessly cold-blooded. It emphasizes not just anger or harshness, but calculated, underhanded viciousness—often directed at people close to the perpetrator.

This expression is almost always used in literary, critical, or moral judgment contexts—not casual speech—and carries strong negative connotation. It functions as a noun phrase (e.g., ‘She has a snake-and-scorpion heart’) and frequently appears after verbs like ‘有’ (yǒu, ‘to have’) or ‘长着’ (zhǎng zhe, ‘to possess’). While the characters individually mean ‘snake,’ ‘scorpion,’ ‘heart,’ and ‘intestines,’ the compound is idiomatic: it’s not about anatomy but about moral character, evoking visceral disgust rather than clinical description.