【Definition】 If you give someone a taste of their own medicine, you do something bad to them in the same way that they have done to you in order to teach them a lesson.【Origins】 The origin of the phrase 'a taste of your own medicine' comes from Aesop's famous story about a swindler who sells fake medicine, claiming that it can cure anything. When he falls ill, people give him his own medicine, which he knows will not work.