Adults can legally obtain and possess marijuana for personal use. Sales usually are regulated and taxed.
No criminal penalty for possession of a small amount. There may be a civil fine or infraction penalty.
Marijuana can be used to treat a variety of medical conditions, such as pain and nausea.
Sources: Associated Press, Law Atlas, Marijuana Policy Project, National Organization for the Reform of Marijuana Laws, National Conference of State Legislatures. Originally published on Oct. 10, 2014. Graphic by Denise Lu, Ted Mellnik and Niraj Chokshi.