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Psilocybin mushrooms Facts

Psychedelic; Substituted tryptamine; Serotonin 2A receptor agonist

Description

Psilocybin mushrooms (Psilocybe spp., Hymenogastraceae) — magic mushrooms, shrooms — are psychoactive fungi comprising roughly 165 species found on every continent except Antarctica.[1] The dominant alkaloid, psilocybin, is converted by the body into psilocin, the compound responsible for the psychedelic state. Psilocin activates serotonin receptors in the cortex, disrupting the brain's default resting network and generating the characteristic psychedelic experience.[2]

Subjective effects include brightened colors, geometric visual patterns, emotional enhancement, and — at higher doses — ego dissolution, where the sense of a separate self temporarily collapses.[3] The experience is shaped decisively by dose, psychological state, and environment; alkaloid content varies up to 11-fold within a single species.[4]

Psilocybin produces no physical dependence and no withdrawal;[5] acute physical toxicity at documented human doses is negligible.[6] The primary danger is psychological — difficult experiences at high doses — with lithium and MAOI co-administration posing the most serious drug interaction risks.[7]

Dose and duration

No dose or duration recorded for any route.

Body and dependence

Acute toxicity
Negligible
Chronic toxicity
Negligible
Physical dependence
None
Psychological dependence
Negligible
Withdrawal
None recorded
Compulsive redosing
Negligible

Tolerance

Builds
Rapid
Fully resets after
7 days
Carries over to
LSD; mescaline; DMT; other serotonergic hallucinogens

Effectslikely at a common dose

Perception
Color enhancement; Visual drifting; Color alteration; Music enhancement; Auditory enhancement; Geometry; Visual breathing; Holotropic state; +25 possible, including Visual haze / noise, Spatial disorientation, Vestibular distortion
Body
Nausea; Pupil dilation; Body high; Body scan awareness; +28 possible, including Muscle tension, Dizziness, Excessive sweating
Thinking
Thought connectivity; Immersion enhancement; Aesthetic enhancement; Introspection enhancement; Openness enhancement; +29 possible, including Suggestibility enhancement, Confusion, Memory suppression
Feeling
Emotional enhancement; Euphoria; +7 possible, including Emotional lability, Anxiety, Paranoia
Self
none likely · 12 possible, including Derealization, Communication suppression, Depersonalization
Time
Time alteration; +4 possible, including Temporal disorientation
Transpersonal
none likely · 1 possible
Awareness
none likely · 4 possible

Who shouldn't take it

Absolute
Active suicidal ideation
Relative
Cardiovascular disease; Pregnancy; Pediatric use; Tramadol use

Combinations61 recorded

Lethal (1)
MAOIs
Dangerous (17)
Dopamine agonists; Lithium; MDMA, MDA; NRIs; GHB, Baclofen; GHB, GBL; Ibogaine; Ketamine, DXM, PCP; Local anesthetics; MDMA, Amphetamines; NDRIs (Wellbutrin); Psychedelics; Salvia, Ibogaine; SNRIs; SSRIs; Stimulants; Synthetic cannabinoids
Caution (37)
See full page: psychedex.org/substances/psilocybin-mushrooms
Not graded (6)
Not listed never means safe.

Seek help immediately if

Most difficulty is psychological (intense fear, panic, confusion) and passes with calm support — the signs below mean seek emergency help:

  • Very high body temperature; hot, dry skin
  • Seizures
  • Chest pain; fast or irregular heartbeat
  • Severe muscle rigidity, tremor, or twitching (possible serotonin syndrome)
  • Cold, pale, or blue fingers/toes — severe vasoconstriction (notably NBOMe / DOx)
  • Persistent vomiting; unconsciousness; uncontrollable agitation or risk of self-harm

What to do

  1. Stay calm and reassure — remind them they took a drug and the effect will pass
  2. Move to a calm, quiet, safe space with low light; reduce noise and sensory input
  3. Keep them from harm — they may act on fear or confusion; stay with them, don't leave them alone
  4. Talk them down gently; don't grab or restrain unless they're in danger
  5. For the medical signs above (overheating, seizure, chest pain, vasoconstriction, unresponsive) call emergency services
  6. If overheating, cool the body; be ready to give rescue breaths / CPR

The experience is time-limited and usually resolves with calm reassurance in a safe setting — psychological first aid, not medication. Serious physical harm is uncommon for classic psychedelics (LSD, psilocybin) but real for some potent phenethylamines (NBOMe, DOx), where hyperthermia, seizures, and vasoconstriction warrant emergency care.

988 Suicide & Crisis LifelineFireside Project: 62-FIRESIDE

Version r4 · Not medical advice

References

  1. [1]
    ^GBIF (2024) Psilocybe taxonomy
  2. [2]
    ^Madsen MK, Fisher PM, Burmester D, et al. (2019) Psychedelic effects of psilocybin correlate with serotonin 2A receptor occupancy and plasma psilocin levels — Neuropsychopharmacology doi:10.1038/s41386-019-0324-9
  3. [3]
    ^Griffiths RR, Richards WA, McCann U, Jesse R (2006) Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance — Psychopharmacology PMID:16826400
  4. [4]
    ^Christiansen AL, Rasmussen KE, Høiland K (1981) The content of Psilocybin in Norwegian Psilocybe semilanceata — Planta Medica PMID:17401967
  5. [5]
    ^Lodetti G, de Bitencourt RM, Rico EP (2024) Classic psychedelics and the treatment for alcoholism — Progress in Neuro-Psychopharmacology & Biological Psychiatry doi:10.1016/j.pnpbp.2024.111129
  6. [6]
    ^Henríquez-Hernández LA, Rojas-Hernández J, Quintana Hernández DJ, Borkel LF (2023) Hofmann vs. Paracelsus: Do Psychedelics Defy the Basics of Toxicology? A Systematic Review — Toxics doi:10.3390/toxics11020148
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