Short answer: Mescaline is a psychedelic found in the peyote cactus and some other cacti, such as San Pedro. Effects last 10 to 12 hours. It is Schedule I in the US, but federal regulations protect the religious use of peyote by members of the Native American Church. Nausea and vomiting are common, and wild peyote is threatened by overharvesting.
Key takeaways
- What it is: Mescaline is a serotonergic psychedelic (phenethylamine) and a Schedule I controlled substance in the US.
- Medical use: None (religious use protected).
- Timing: effects start in 1 to 2 hours and last 10 to 12 hours.
- Most dangerous mix: Lithium, which can cause seizures and dangerous reactions reported.
- Naloxone: it does not reverse this drug, but give it whenever opioids could be involved.
- Dependence risk: Low.
- Legal route: none. Schedule I substances cannot be prescribed.
What is mescaline?
Mescaline is the main psychoactive compound in peyote, a small spineless cactus native to Texas and Mexico, used in Indigenous ceremonies for thousands of years. It is also found in San Pedro and related cacti from the Andes.
Mescaline produces vivid colors and visual patterns, altered sense of time and self, and strong emotions. Physical effects include nausea and vomiting (common early on), dilated pupils, sweating, and raised heart rate and temperature.
Quick facts
| Fact | Mescaline |
|---|---|
| Chemical name | 3,4,5-trimethoxyphenethylamine |
| Sources | Peyote (Lophophora williamsii); San Pedro and Peruvian torch cacti |
| Drug class | Serotonergic psychedelic (phenethylamine) |
| US legal status | Schedule I; religious exemption for peyote in the Native American Church |
| How it is used | Dried cactus "buttons" chewed or brewed as tea; powder |
| Onset | 1 to 2 hours |
| Duration | 10 to 12 hours |
| Half-life | About 6 hours |
| Physical dependence | No |
How long does mescaline last?
- Starts working: 1 to 2 hours
- Effects last: 10 to 12 hours
- Half-life: About 6 hours
About 10 to 12 hours.
Timing varies with the dose, the form, how it is taken, liver and kidney function, age, and other drugs taken at the same time.
What are the biggest risks of mescaline?
Psychological risks: fear, confusion, and risky behavior during the long experience; higher risk of lasting effects in people with a history of psychosis.
Physical risks: vomiting and raised heart rate and blood pressure; caution with heart disease.
Misidentification and mislabeling: products sold as mescaline are sometimes other drugs.
What should you never mix with mescaline?
| Combined with | What happens | Risk level |
|---|---|---|
| Lithium | Seizures and dangerous reactions reported | Avoid |
| MAOIs (and ayahuasca) | Greatly intensified, unpredictable effects | High risk |
| SSRIs and SNRIs | Usually blunted effects; serotonin syndrome possible with some combinations | Use caution |
| Cannabis | More intense, sometimes frightening experiences | Use caution |
| Stimulants (amphetamines, cocaine) | Anxiety, heart strain, overheating | Use caution |
Check any combination with the DoseUses combination checker or ask a pharmacist.
What are the signs of a mescaline overdose, and what should you do?
Physical overdose is uncommon because large amounts are needed and vomiting is common. Very high doses can cause high blood pressure, fast heartbeat, and dangerous agitation.
If someone is having a dangerous reaction
- Call 911 for a seizure, chest pain, a very high temperature, trouble breathing, unresponsiveness, or if the person may harm themselves or others.
- Move them to a quiet, safe place away from roads, water, heights, and crowds. Stay with them and speak calmly.
- Do not leave the person alone and do not give them other drugs or alcohol to calm them down.
- If they become unresponsive, place them on their side and give naloxone in case opioids are involved.
Is mescaline addictive?
Mescaline is not considered physically addictive and does not cause a withdrawal syndrome. Tolerance builds quickly and is shared with LSD and psilocybin. Some people use it compulsively, but this is uncommon.
See the withdrawal timelines and the full mescaline withdrawal guide.
Is mescaline legal?
Mescaline is a Schedule I controlled substance under federal law, meaning it is considered to have a high potential for abuse and no currently accepted medical use. It cannot be prescribed, and possessing, making, or selling it is a federal crime.
- Possession: under federal law, a first conviction for possessing any controlled substance without a valid prescription can bring up to one year in prison and a minimum fine of $1,000. Penalties rise with prior convictions.
- Selling or sharing: distribution carries much heavier federal penalties, which increase with the amount involved and are higher still if the drug causes death or serious injury.
- State law: states set their own penalties, and most drug cases are prosecuted under state law. Penalties range from a civil fine to long prison terms depending on the state, the amount, and prior record.
Outside the United States
| Country | Status |
|---|---|
| Mexico | Prohibited except for Indigenous religious use |
| Canada | Schedule III; peyote itself exempt |
| United Kingdom | Class A (mescaline); cacti not controlled unless prepared |
| International | Mescaline: Schedule I of the 1971 Convention; peyote cactus not listed |
Frequently asked questions about mescaline
How long does mescaline last?
About 10 to 12 hours.
Is peyote legal for anyone in the US?
Only for members of the Native American Church in religious ceremonies.
Is San Pedro cactus legal?
Growing it as an ornamental plant is generally legal, but extracting or consuming mescaline is illegal.
Why is peyote endangered?
It grows very slowly and wild populations in Texas and Mexico have been overharvested.
Sources
- Psychedelic and Dissociative Drugs, National Institute on Drug Abuse.
- Controlled Substance Schedules, DEA Diversion Control Division.
- 21 U.S.C. 844, Penalties for simple possession, Legal Information Institute, Cornell Law School.
- 21 U.S.C. 841, Prohibited acts A (trafficking penalties), Legal Information Institute, Cornell Law School.
- 21 CFR 1307.31, Native American Church (peyote exemption), Electronic Code of Federal Regulations.
- National Helpline, Substance Abuse and Mental Health Services Administration.
- FindTreatment.gov, Substance Abuse and Mental Health Services Administration.
- International drug control conventions, United Nations Office on Drugs and Crime.
This guide summarizes the sourced DoseUses Mescaline profile, written from FDA labels, DEA rules, and federal health agencies. It is educational and is not medical advice. Last updated October 5, 2026.
