1. What the law is
A psilocybin bill passed the Missouri House 137-11 in April 2026 and then went quiet. HCS HBs 1717 & 1643 would have required the state to study psilocybin therapy for veterans and first responders, funded by $2 million in research grants, with participants allowed to possess psilocybin only while enrolled in a supervised study. It reached the Senate as SCS HCS HBs 1717 & 1643, went onto the informal calendar on 7 May 2026, and stayed there through the 15 May 2026 adjournment. It was never truly agreed and finally passed, so nothing is enacted. Psilocybin is Schedule I in Missouri and possession is a crime.
Psilocybin is illegal in Missouri, where it is classified as a Schedule I controlled substance under the Missouri Comprehensive Drug Control Act, with psilocybin and psilocyn listed by name as hallucinogenic substances in RSMo Section 195.017. Possession, manufacture, and distribution are criminal offenses under RSMo Chapter 579, with possession of a controlled substance generally charged as a felony. No statute authorizes any legal, medical, or supervised use of psilocybin in the state.
Missouri has not enacted any law decriminalizing or legalizing psilocybin, and the substance remains illegal statewide. Legislative activity has been confined to research and study proposals. During the 2026 session, the Missouri House passed combined legislation, HCS HBs 1717 & 1643, by a vote of 137-11 on April 2, 2026; as passed by the House, the measure would have directed the state to study psilocybin therapy for veterans and first responders, funded by $2 million in research grants, and would have permitted participants to possess psilocybin only while enrolled in a supervised state study. The measure reached the Senate calendar with a Senate committee substitute, but its final passage before the General Assembly's May 15, 2026 adjournment is unconfirmed. Because no psilocybin bill has been confirmed as enacted, the proposed study creates no current legal access; psilocybin remains a Schedule I substance under RSMo 195.017 and possession remains a crime today.
2. Trials in Missouri
Interventional psilocybin trials with at least one site in Missouri, as their sponsors filed them with ClinicalTrials.gov, EU CTIS and ISRCTN. Each row links to the registry record, which sets out who may take part.
Recruiting or opening counts trials recruiting now, not yet recruiting, or enrolling by invitation. Closed counts trials terminated, suspended, withdrawn or left unverified by their sponsors.
| Registry ID | Trial | Phase | Sponsor | Status | Start date |
|---|---|---|---|---|---|
| NCT07582120 | Psilocybin-Assisted Therapy as a Treatment for Depression (opens in new tab)Site at Washington University School of Medicine, St Louis | Phase Phase 2 | Sponsor Washington University School of Medicine | Status Not yet recruiting | Start date |
| NCT06308653 | Psilocybin for Major Depressive Disorder (MDD) (opens in new tab)Site at Washington University School of Medicine, St Louis | Phase Phase 3 | Sponsor Usona Institute | Status Active, not recruiting | Start date |
| NCT05601648 | PET Synaptogenesis After Psilocybin In DEpression Recovery (opens in new tab)Site at Washington University School of Medicine, St Louis | Phase Phase 2 | Sponsor Washington University School of Medicine | Status Withdrawn | Start date |
| NCT05711940 | Efficacy, Safety, and Tolerability of Two Administrations of COMP360 in Participants With TRD (opens in new tab)Site at St. Charles Psychiatric Associates - Midwest Research Group, Saint Charles | Phase Phase 3 | Sponsor COMPASS Pathways | Status Active, not recruiting | Start date |
| NCT05624268 | Efficacy, Safety, and Tolerability of COMP360 in Participants With TRD (opens in new tab)Sites in Columbia, Saint Charles, St Louis | Phase Phase 3 | Sponsor COMPASS Pathways | Status Completed | Start date |
| NCT04501653 | Precision Functional Brain Mapping in Psilocybin (opens in new tab)Site at Washington University, St Louis | Phase Phase Early 1 | Sponsor Washington University School of Medicine | Status Completed | Start date |
ClinicalTrials.gov data courtesy of the U.S. National Library of Medicine.
3. History
The legal events behind this entry, dated and oldest first. Our own reviews and corrections are listed under Changes to this record.
Current version of RSMo Section 195.017 takes effect, listing psilocybin and psilocyn as Schedule I hallucinogenic substances under the Missouri Comprehensive Drug Control Act.
Missouri House passes HCS HBs 1717 & 1643 by a vote of 137-11; as passed, the bill would require a state study of psilocybin therapy for veterans and first responders, with $2 million in research grants and possession permitted only while enrolled in a supervised study.
Missouri General Assembly adjourns sine die; final passage and enactment of HCS HBs 1717 & 1643 is unconfirmed, and no psilocybin law is confirmed as enacted.
4. Proposed laws
None. The 2026 vehicle, SCS HCS HBs 1717 & 1643, died unpassed: the Missouri House's bill page records its last action as 05/07/2026 Placed on Informal Calendar and its progress tracker shows Truly Agreed and Sent to Governor both Incomplete. The Senate companions SB 1682 (McCreery) and SB 1767 (Brattin) did not reach a floor vote (Missouri House bill page for HB 1717 and Missouri Senate 2026 bill list, both checked 16 Aug 2026).
5. Common questions
Is psilocybin legal in Missouri?
No. Psilocybin is a Schedule I controlled substance in Missouri under RSMo Section 195.017, where psilocybin and psilocyn are listed by name. Possession, manufacture, and distribution are criminal offenses, and no state law authorizes legal or medical use.
Is psilocybin decriminalized anywhere in Missouri?
No. Missouri has not enacted statewide decriminalization, and no Missouri municipality has adopted an ordinance recognized under state law that removes criminal penalties for psilocybin. Possession remains a criminal offense throughout the state.
What did the 2026 Missouri psilocybin bill do?
HCS HBs 1717 & 1643, which the Missouri House passed 137-11 on April 2, 2026, would have directed the state to study psilocybin therapy for veterans and first responders, funded by $2 million in research grants. Under the House-passed version, participants could possess psilocybin only while enrolled in a supervised state study. The bill reached the Senate calendar, but its final passage before the May 15, 2026 adjournment is unconfirmed.
Does the proposed psilocybin study bill make psilocybin legal in Missouri now?
No. No psilocybin bill has been confirmed as enacted in Missouri, so the proposed study creates no current legal access. Psilocybin remains a Schedule I substance under RSMo 195.017, and possession remains a crime today.
What is the penalty for psilocybin possession in Missouri?
Possession of psilocybin is prosecuted as possession of a controlled substance under Missouri law (RSMo Chapter 579) and is generally charged as a felony. Penalties depend on the specific charge, the quantity, and the circumstances of the offense; consult a licensed Missouri attorney for case-specific guidance.
Are magic mushrooms ("shrooms") legal in Missouri?
"Magic mushrooms" and "shrooms" are common names for fungi that contain psilocybin, and this entry states the law on psilocybin itself, which some laws treat separately from the fungus. Psilocybin is illegal in Missouri.
Sources
This entry's status is checked against the primary sources below, and the methodology explains how each entry is graded for confidence.
- 1.house.mo.gov (opens in new tab) · house.mo.gov
- 2.missouriindependent.com (opens in new tab) · missouriindependent.com
This entry is for information only and is not legal or medical advice. Laws change, and enforcement can differ from the letter of the law, so check the current position against the primary sources above before relying on it.
Changes to this record
2 changes on file, the latest on . Show allHide
Every change we have made to this record, dated, corrections included. Nothing changes silently.
Missouri's entry now says plainly what happened to the psilocybin study bill. It passed the House in April 2026, sat on the Senate's informal calendar from 7 May, and was never truly agreed before the session ended.
Missouri's psilocybin bills all stopped at the study stage, and the fate of the one the House passed in April 2026 was still unresolved at the time. The entry was corrected from mixed to illegal.
Psilocybin Media Group. "Missouri: psilocybin legal status." The Psilocybin Record, accession US-MO-001, version of 23 Aug 2026. https://psilocybinlegalization.com/record/missouri