Dr Young’s Ideal Rectal Dilators were made from jelly-like material, with one set the dilators coming in a set of four “torpedolike” rods, from a little half-incher to a four-inch long and inch-wide version (ouch!).
Writing in a 1893 medical journal, the eponymous Dr Young touted the devices as a cure for insanity, insisting that it could cure 75% of people considered insane "in a few weeks' time". The device grew in its alleged benefits the longer that it was on the market, benefiting from lax regulation on medical devices.
Read more about it and how the Federal Food, Drugs and Cosmetics Act of 1938 put an end to all the fun over at PinkNews: Butt plugs used to be sold as a ‘miracle cure’ for headaches and acne.