Mescaline: Compound Guide

Urgent first. If someone has chest pain, a seizure, trouble breathing or is dangerously agitated or confused after taking a psychoactive substance or cactus product, call 911 or US Poison Help at 1-800-222-1222. For a mental health crisis in the US, call or text 988.

A note on respect. Peyote is a sacrament of the Native American Church and of other Indigenous peoples of North America. This page covers the compound, not ceremonies, and it gives no amounts, preparation, sourcing or plant identification. Evidence labels: insufficient evidence, promising but limited, preclinical (cells/animals only).

What mescaline is

Mescaline (3,4,5-trimethoxyphenethylamine) is a naturally occurring alkaloid found in cacti, mainly the peyote cactus (Lophophora williamsii) and cacti of the Echinopsis genus. A review traces evidence of use back about 5,700 years. [1] NIDA says mescaline is also made in a lab (synthetic). [2] It is a phenethylamine, not a tryptamine like psilocybin or DMT, and a pharmacology review says its effects are mainly attributed to serotonin 5-HT2A and 5-HT2C receptors and also include sympathomimetic (stimulant-like) signs. [3] NIDA groups it among the psychedelic drugs. [2]

Mescaline vs the plants that contain it

The compound is not the plant. Peyote and San Pedro are different cacti that both contain mescaline; see peyote, San Pedro cactus and other mescaline-containing cacti. A laboratory study of 14 kinds of Echinopsis ("San Pedro") found all contained mescaline, with concentrations across them spanning two orders of magnitude, so no plant has a "typical" level. [4] This page does not help identify cacti. For cultural background see peyote and its traditional contexts and mescaline-cactus traditional contexts. A comparison with another compound is at mescaline vs psilocybin.

History

A review of Mesoamerica reports archaeological evidence of peyote use dating back more than 5,000 years. [5] Peyote use continues in the Native American Church, whose members' use is described as religious. [6]

What research shows

• Effects. In humans, mescaline can induce euphoria, hallucinations and psychotomimetic effects. [1]
• Treatment uses: insufficient evidence. The review "Mescaline: the forgotten psychedelic" notes research has been limited since the early 1970s and calls mescaline potentially beneficial in clinical settings, which is a statement about potential. [1] A 2026 systematic review found 66 studies met inclusion criteria and only 10 were suitable for analysis; reported effects included improvements in depression scales, but the literature was limited and of highly variable quality, preventing definitive conclusions. [7]
• Randomized trials: Proper evidence not found in the reviews we read for a completed modern randomized trial of mescaline as a treatment.
• Dependence. A pharmacology review says addiction and dependence are practically absent, with the caveat that most reports had no laboratory confirmation of what was taken. [3]

Risks

• Intoxications appear mostly mild, but the same review notes psychosis-like states and sympathomimetic signs. [3]
• In the 2026 systematic review, hypertension, headache, nausea and vomiting were frequently reported effects, and the safety profile still needs research. [7]
• Heart conditions: data on psychedelics in people with cardiovascular disease are lacking. [8]
• Pregnancy: a scoping review found one eligible human study on mescaline/peyote among 23 sources, and said sparse human evidence cannot reliably estimate risk. [9]
• Drug interactions: a systematic review found only 4 human studies of mescaline interactions with other drugs. [10] We give no combining advice. See psychedelic drug interactions and toxicology.

Conservation

In the United States, peyote only grows naturally in Texas, and reporting in 2025 said development, over-harvesting and poaching have reduced it. [6] Authors of the Indigenous Peyote Conservation Initiative describe the plant as threatened and ask non-Indigenous people not to buy peyote or use it outside a bona fide Native American Church context. [11] Read more at peyote conservation and Indigenous traditions, ethics and conservation.

Legal status

Not legal advice; laws change. In the United States, mescaline and peyote (all parts of Lophophora williamsii) are each listed in Schedule I of 21 CFR 1308.11 (eCFR, read 2026-10-22). [12] A separate rule, 21 CFR 1307.31, says the Schedule I listing of peyote does not apply to the nondrug use of peyote in bona fide religious ceremonies of the Native American Church. [13] That exemption is written about peyote and Native American Church members; it is not a general permission for mescaline or other cacti. Other countries and San Pedro: not verified. See psychedelic legal status.