a pill of blue mass, used in medicine chiefly as a cathartic.
Origin of blue pill
First recorded in 1785–95
Also called mercury mass.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for blue pill
Historical Examples of blue pill
The time will come, we may hope, when doctors will prescribe bird-gazing instead of blue-pill.Birds in the Bush