Most expressions in Chinese about the dog, for example, "a homeless dog", "a mad dog", "a running dog" and "a dog catching a mouse", have bad meanings.

中文中关于狗的大多数表达，如“流浪狗”、“疯狗”、“走狗”和“狗抓老鼠”，都有不好的含义。

youdao

You can be mad as a mad dog at the way things wents.

有时事与愿违，你可以像疯狗一样咆哮。

youdao

Ancient Romans, it seems, believed that the bite of a mad dog could only be cured by burning the dog's hair and drinking it with water.

古罗马人似乎相信，被疯狗咬了以后，只能烧掉那只狗身上的毛，加在水里喝下去，才会治好。

youdao

Nearby,on massive balloons, one can see the Colonel of a decade later, the man who backed extremists and terrorists, a pariah dubbed by the United States the "Mad Dog of the Middle East".

VOA: standard.2009.08.29

Michael (Mad Dog) Harris, a 60-year-old general contractor from Phoenix, flies to matches with his wife, Suzanne (Ramblin' Rose), in their Piper Aztec.

FORBES: Draw, You Varmint!

Given the negative externalities associated with consuming alcohol, however, the movement to higher priced, heavier-tasting, craft beers that are not guzzled like Mad Dog might not be a bad thing.

FORBES: With InBev Suit, Feds Fight To Keep Beer Cheap For Young Blue-Collar Men. Maybe That's Not A Good Idea.