What is the polite way to respond to a sneeze in Chinese?
From Wikipedia: [which funnily enough has a Responses To Sneezing page]

Usual Responses and Notes


  多喝点水 (Duō hē diǎn shuǐ), 一百岁 (yì bǎi suì), 保佑你 (bǎo yòu nǐ) or 长命百岁 (chánɡ mìnɡ bǎi suì); frequently, listeners do not comment on the sneeze.


meaning:


  "Drink more water","May you live for a hundred years.", "bless you." or "May you live to one hundred years."


sneezer reply:


  呵呵,不好意思 (bù hǎo yì si)


meaning:


  "He he (No meaning, just smile politely)","Excuse me."


tl;dr: frequently, listeners do not comment on the sneeze.



Here's some info on Cantonese

Usual Responses and Notes


  大吉利事. Sneezing in Southern Chinese culture means that someone is speaking ill behind your back.


meaning:


  "A great fortunate occurrence."    


sneezer reply:


  唔好意思   


meaning:


  "Sorry."