The principal active ingredient in Paregoric is powdered opium. Trapper makes a pun during the poker game comparing a "pair of twos" with paregoric. However, Laudanum contains 10 milligrams of morphine per milliliter, 25 times more than Paregoric. The medicine was similar to paregoric; a tincture of opium and camphor. The current formula for Paregoric, U.S.P. should not be assumed to be universal. Some states further limited the sale of paregoric, or banned over-the-counter sales entirely. Paregoric is currently listed in the United States Pharmacopeia. The children were drugged with paregoric to keep them quiet while slave patrols rode by. Paregoric was used in various formulations for hundreds of years.