give someone a taste of one’s own medicine

(idiom) use the same methods as your enemy

Example Sentences:

When Shania’s boyfriend kissed another girl, she decided to give him a taste of her own medicine, so she cheated on him.

A: My ex-wife is suing me!
B: Why?
A: She says I have to pay her money!
B: You should give her a taste of her own medicine! Sue her!

From the Blogs:

Paxman gets taste of own medicine after PR jibe
Media:

Similar idioms:

1. fight fire with fire
2. take one’s medicine
3. laughter is the best medicine
4. acquired taste