own medicine, a dose/taste of one's

dose of one's own medicine

Also, taste of one's own medicine. Repayment or retaliation, as in It's time we gave them a dose of their own medicine and simply forget to call them back , or Joe was upset at being left out, but they were just giving him a taste of his own medicine . [Late 1800s]
See also: dose, medicine, of, own
The American Heritage® Dictionary of Idioms by Christine Ammer.

own medicine, a dose/taste of one's

Repayment in kind; tit for tat. Although the idea is hardly new, the medicinal metaphor dates only from the late nineteenth century. V. Perdue used it in The Singing Clock (1941): “It was only fair for them to get a taste of their own medicine.”
See also: dose, of, own, taste
The Dictionary of Clichés by Christine Ammer
See also:
  • at will
  • beat (one) at (one's) own game
  • beat somebody at their own game
  • beat someone at his or her own game
  • beat someone at their own game
  • (the) odds are (that)
  • a place to call own
  • blow (one's) own trumpet
  • be hoist by (one's) own petard
  • be hoist with one's own petard