Together, 流(liú) + 鼻(bí) + 涕(tì) creates a vivid, literal picture: “flow nose mucus.” It's a straightforward combination that means exactly what it sounds like.
While a “runny nose” might seem like a simple medical term, its usage touches upon cultural norms around health in China. In general, Chinese culture is quite direct when it comes to describing physical symptoms. Unlike in some Western cultures where one might start with a vague phrase like “I'm feeling under the weather,” it is very common and normal in China to state the specific problem directly: “我感冒了，流鼻涕，还头疼” (Wǒ gǎnmào le, liú bítì, hái tóuténg) - “I have a cold, a runny nose, and also a headache.” This directness is not considered impolite but rather efficient and clear. Furthermore, in the context of Traditional Chinese Medicine (TCM), the type of nasal discharge can be significant. A clear, watery discharge (清鼻涕 - qīng bítì) is often associated with a “wind-cold” (风寒 - fēnghán) invasion, prompting remedies like hot ginger tea. A thick, yellow discharge (黄鼻涕 - huáng bítì) might indicate “wind-heat” (风热 - fēngrè), suggesting different treatments. While a beginner doesn't need to know TCM theory, understanding this background helps explain why someone might ask about the specifics of your runny nose.
流鼻涕 (liú bítì) is an everyday term used across all levels of formality.
The connotation is neutral. It is a simple statement of a physical fact and is not considered rude or gross to say.