For most of American
history, growing and using marijuana was legal under both federal law
and the laws of the individual states. By the 1840s, marijuana’s
therapeutic potential began to be recognized by some U.S. physicians.
From 1850 to 1941 cannabis was included in the United States
Pharmacopoeia as a recognized medicinal. By the end of 1936, however,
all 48 states had enacted laws to regulate marijuana. Its decline in
medicine was hastened by the development of aspirin, morphine, and then
other opium-derived drugs, all of which helped to replace marijuana in
the treatment of pain and other medical conditions in Western medicine.
Cannabis in American History