Blue pill


 * For the blue pill in The Matrix and references thereto from other pop media, see bluepill

In medicine, the blue pill, also called the pilula hydrargyri, was a remedy prescribed for various ailments, particularly constipation. It contained 1/3 elemental mercury by weight, mixed with marshmallow, honey of rose, liquorice, glycerin, and inert ingredients to form pills of about 48 grains in weight.

A combination of the blue pill, and a mixture called the common black draught, was a standard cure for constipation in early 19th century England and elsewhere. It was particularly valued on ships of the Royal Navy, where sailors and officers were constrained to eat rock-hard salted beef and pork, old, stale biscuits, and very little fruit, fiber, or other fresh food once they were some distance from land on a long voyage.