Definition
to treat someone in the same negative way they have treated others
以其人之道，还治其人之身。
He always makes fun of other people's mistakes, so when he made one, we decided to give him a taste of his own medicine.
他总是取笑别人的错误，所以当他犯错时，我们决定以其人之道还治其人之身。
The bully often harassed weaker students, but when he encountered someone stronger, he got a dose of his own medicine.
那个霸凌者经常骚扰较弱的学生，但当他遇到更强的人时，他就尝到了自己的苦果。
She had been lying to me, so I decided to give her a taste of her own medicine and let her know how it felt to be deceived.
她一直在欺骗我，所以我决定以其人之道还治其人之身，让她知道被欺骗的感觉。