SPECIALTY TOPICS · GUIDE
What Are Psychedelics? Natural, Semisynthetic and Synthetic Substances
What psychedelics are, how the words psychedelic, hallucinogen and entheogen are used, and which substances are natural, semisynthetic or synthetic, with where each is covered.
Content last updated . This page has not been medically reviewed.
Back to Psychedelic TherapyPsychedelics in plain terms
Psychedelic and dissociative drugs can temporarily alter a person's mood, thoughts and perception of reality. The US National Institute on Drug Abuse (NIDA) says many of these drugs derive from plants and fungi, some have been used for thousands of years in traditional or religious rituals, and some are synthetic, meaning lab-made. [1] People report using them for many reasons, including new experiences, spiritual exploration and hoping to improve well-being, but NIDA says more research is needed to know whether they work for those purposes. [1]This library is education only. It describes what substances are, what research shows and where risks and legal limits lie. It does not tell anyone how to find, prepare or use them.
The words people use
A 2022 scientific primer explains that "psychedelic" comes from the Greek for "mind manifesting" and was first proposed by Humphry Osmond in 1956. [2] So an entheogen is not a separate chemical class. It is a way of describing a substance when it is used in a spiritual setting. Many peoples who use sacred plants describe them in their own words and traditions, and this site tries to use those terms respectfully. See Indigenous Traditions, Ethics and Conservation. The broader word "psychoactive" is explained in What Does Psychoactive Mean?.How researchers group these substances
NIDA says researchers debate how to classify these drugs and generally group them by how they work in the brain. [1]| Group | How it works (NIDA) | Examples (NIDA) | Guide |
|---|
[1]
[3] On this site, "atypical" is our own shorthand for natural substances that do not fit the classic serotonin pattern. It is not an official category.
Natural, semisynthetic and synthetic
"Natural psychedelics" on this site means substances that occur in a plant or fungus. Natural origin says nothing about safety. The library also covers semisynthetic and synthetic substances because readers meet them in the same news stories and clinical research. See Natural vs Synthetic Psychoactive Substances.| Substance | Origin as described in sources | Guide |
|---|---|---|
| Psilocybin | Certain mushrooms found on nearly every continent [4] | More about Psilocybin → |
| Mescaline | Peyote and Echinopsis (San Pedro) cacti [5] | More about Mescaline → |
| DMT | Leaves of the Psychotria viridis bush, a plant in ayahuasca [6] | More about DMT → |
| Ibogaine | The African rainforest shrub Tabernanthe iboga [7] | More about Ibogaine → |
| Salvinorin A | The sage Salvia divinorum [8] | More about Salvinorin A → |
| Ibotenic acid and muscimol | The Amanita muscaria mushroom [9] | More about Ibotenic acid and muscimol → |
Education only
For medicines you take, see how interactions work. For how research is labeled here, see how we label evidence. The library's overview is on the area hub.Frequently asked questions
What is the difference between a psychedelic and a hallucinogen?
The words overlap. "Psychedelic" is often used for substances acting on serotonin 5-HT2A receptors, while "hallucinogen" is older and broader, and some people use it for all of these drugs. [1]
What does entheogen mean?
It describes substances when they are used in a spiritual context. It stresses the spiritual side rather than a chemical type. [2]
Are natural psychedelics safer than lab-made ones?
No general rule supports that. NIDA lists both natural and lab-made substances among those with risks and says effects vary widely. [1]
Are these substances approved medicines?
[13]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Why the details matter for safety
NIDA says effects are hard to predict and depend on the amount and potency, a person's biology, mood, expectations and surroundings, and that contaminants or other substances can change the effect. [1] Some of these substances, including ibogaine and PCP, have been associated with a small number of deaths and serious effects. [1] Mixing with medicines that raise serotonin is suspected, in rare reported cases, of causing serotonin toxicity. [1] Review the risks in Psychedelic Adverse Effects and Contraindications.
References
- National Institute on Drug Abuse, Psychedelic and Dissociative Drugs. Read 2026-10-22.
- Kelmendi B et al. Psychedelics. Curr Biol. 2022;32(2):R63-R67. Read 2026-10-22 (abstract on PubMed).
- US Food and Drug Administration, Psychedelic Drugs: Considerations for Clinical Investigations, Guidance for Industry (July 2026). Read 2026-10-22.
- National Institute on Drug Abuse, Psilocybin (Magic Mushrooms). Read 2026-10-22.
- Vamvakopoulou IA et al. Mescaline: The forgotten psychedelic. Neuropharmacology. 2023;222:109294. Read 2026-10-22 (abstract on PubMed).
- Dos Santos RG, Hallak JEC. Ayahuasca: pharmacology, safety, and therapeutic effects. CNS Spectr. 2024;30(1):e2. Read 2026-10-22 (abstract on PubMed).
- Litjens RP, Brunt TM. How toxic is ibogaine? Clin Toxicol (Phila). 2016;54(4):297-302. Read 2026-10-22 (abstract on PubMed).
- Grundmann O et al. Salvia divinorum and salvinorin A: an update on pharmacology and analytical methodology. Planta Med. 2007;73(10):1039-46. Read 2026-10-22 (abstract on PubMed).
- Michelot D, Melendez-Howell LM. Amanita muscaria: chemistry, biology, toxicology, and ethnomycology. Mycol Res. 2003;107(Pt 2):131-46. Read 2026-10-22 (abstract on PubMed).
- National Institute on Drug Abuse, Psychedelic and Dissociative Drugs as Medicines. Read 2026-10-22.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.