A bitter pill to swallow is a truth that people do not want to face but one that cannot be avoided. Like a pill must be swallowed, this fact must be taken in. However, because it is a “bitter” pill, it may hurt or feel uncomfortable to accept.
Most often, a bitter pill to swallow is information that people do not want to know because it hurts their pride or feelings. However, there is no getting away from this information.
Similar variations of this phrase are a tough pill to swallow and a hard pill to swallow.
The phrase pill to swallow has been in use since the 1600s. In the 1700s, Rapin Thoyras, who wrote about the history of France and Italy, added the word bitter to the phrase:
This event, which happened the 7th of September, N.S. was immediately follow’d by the relieving of time after, with the total expulsion of the French out of all Italy; a bitter pill to swallow.
Since then, people have referred to an uncomfortable set of facts as “a bitter pill to swallow” or “a hard pill to swallow.”
