Cannabis in Missouri is illegal but decriminalized. Medical use was legalized in 2018 through a ballot initiative to amend the state constitution.
Partial decriminalization (2014)
In May 2014, Senate Bill 491 was enacted which reduced penalties for certain cannabis offenses. In particular, it eliminated the threat of jail time for first-time possession of up to 10 grams. The bill also reduced penalties related to the sale and cultivation of cannabis, and eliminated the ban on probation or parole for third-time drug felony convictions. It passed the Senate by a 29–2 vote and the House by a 140–15 vote, then became law without receiving the signature of Gov. Jay Nixon. SB 491 did not take effect until January 2017. Although penalties for cannabis were reduced under SB 491, possession of small amounts is still treated as a misdemeanor crime. For this reason the National Organization for the Reform of Marijuana Laws considers Missouri to only have partially decriminalized cannabis.
In July 2014 Governor Jay Nixon signed into law the Missouri Medical Marijuana Bill, legalizing the use of CBD oil to treat persistent seizures. House Bill 2238 "allows the Department of Agriculture to grow industrial hemp for research purposes and allows the use of hemp extract to treat certain individuals with epilepsy". A neurologist must determine that the epilepsy does not respond to at least three treatment options in order for a person to be eligible. HB 2238 only allows hemp extract that contains at least 5% cannabidiol and no more than 0.3% tetrahydrocannabinol. In 2015 the state issued licenses to two non-profits to grow cannabis for oil to be sold to patients.
Medical cannabis legalization (2018)
In November 2018, Missouri residents approved with 66% of the vote a ballot measure to legalize the medical use of cannabis. The measure allowed qualified patients to grow up to six cannabis plants and purchase an amount of cannabis per month to be determined by state regulators. The measure set a 4% tax rate on medical cannabis sales with proceeds to be earmarked for services for military veterans. Although some qualifying conditions are specified, the law additionally allows cannabis to be recommended for any "chronic, debilitating or other medical condition" as determined by a physician, along with any terminal illness. Also on the ballot with Amendment 2 were two other medical cannabis initiatives that were defeated. Amendment 3 contained a narrower set of qualifying conditions, a higher tax rate of 15 percent, and would not have allowed home cultivation. It failed with 32 percent of the vote. A third measure, Proposition C, was a statutory change as opposed to a constitutional amendment. It set a two percent tax rate and also contained no home grow provision. It failed with 44 percent of the vote.
In November 2004, a ballot measure to decriminalize cannabis in Columbia passed with 61% of the vote. The measure stipulated that possession of up to 35 grams was to be processed in municipal court as a non-criminal offense, punishable by a maximum fine of $250. Also passed with 69% of the vote was an initiative to allow the use of cannabis with a physician's approval. A year earlier, in April 2003, a ballot measure to decriminalize cannabis in the city failed with 42% of the vote.
In August 2012, the city council of Springfield voted 6–3 to enact a citizen-led petition to decriminalize small amounts of cannabis. It was then repealed one month later, however, in effect blocking the proposal from appearing on the ballot. Since city council did not have this explicit power, organizers of the petition denounced the council's actions which they deemed to be illegal. A lawsuit was filed in federal court, and in April 2015 the city settled with the petition originators in the amount of $225,000.
St. Louis (2013)
In April 2013, the St. Louis Board of Aldermen voted 22–3 to allow police to cite individuals instead of arresting them for small amounts of cannabis. Cited persons would be processed in municipal court and subject to a fine in the range of 100 to 500 dollars. The law went into effect in June 2013. Penalties were further reduced in February 2018 when the Board of Aldermen voted 24–0 to set a $25 fine for possession of up to 35 grams.
In April 2017, Kansas City residents approved with 75% of the vote a ballot measure to decriminalize up to 35 grams of cannabis. The measure eliminated the threat of jail time and reduced the penalty to a $25 fine. The penalty was later completely eliminated in July 2020 by a 9–4 city council vote.
Polling
In January 2014, St. Louis Mayor Francis Slay posted an informal poll on his mayoral website asking constituents whether or not they were in favor of the legalization of recreational cannabis. The published results showed that over 90% of the people who voted were in favor of legalization and 66% supported taxation upon its sale. Twenty-eight percent indicated they had used the drug in the past week.