“以牙还牙，以眼还眼”的英语翻译？

tit for tat
最常用

以前有人问过， 有更多的回答。查此论坛。

give sb some of his own medicine
我背过的 绝对正确

以其人之道还治其身
dose sb. with his own physic
pay sb. back in his own coin
serve sb. with the same sauce

tit for tat 是比较经典的翻译

An eye for an eye, and a tooth for a tooth