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Grayanotoxins are a family of diterpenoid toxins produced by plants of the Ericaceae family, notably certain Rhododendron species, and they are the active constituents of the "mad honey" made by bees foraging on those flowers. They bind voltage-gated sodium channels in the open state and prevent their inactivation, producing prolonged membrane depolarization and heightened vagal tone; at nerve terminals grayanotoxin III has been shown to increase calcium-dependent release of both GABA and glutamate. Clinically this manifests as dizziness, nausea, hypersalivation, and, in more serious cases, marked hypotension and bradyarrhythmias including atrioventricular block. The margin between a mild effect and dangerous cardiovascular toxicity is narrow; management is largely supportive with intravenous fluids and atropine, and outcomes are usually favorable with prompt recognition.
- Historically used in folk medicine (not endorsed)
- Of toxicological research interest
- Mild altered sensation at very low exposure
- Binds open sodium channels causing sustained depolarization
- Dangerously slow heart rate
- Low blood pressure and fainting
- Nausea, vomiting, sweating
Mechanism
Grayanotoxins bind to voltage-gated sodium channels and hold them in an open, activated state, so nerve and muscle cells cannot properly reset between signals. This sustained sodium influx over-excites the vagus nerve and disrupts normal cardiac and neuromuscular signaling, which is why the main effects are slowed heart rate, low blood pressure, dizziness, nausea and altered consciousness. It is fundamentally a toxin acting on ion channels rather than a receptor-targeted psychoactive.
receptor fingerprint
Voltage-gated sodium channelsOpener (holds channel open)
Safetyrisks and cautions, not medical advice
Grayanotoxin poisoning (from mad honey or plant material) can cause severe bradycardia (dangerously slow heart rate), profound low blood pressure, fainting, vomiting and, in serious cases, heart-rhythm collapse; medical treatment is sometimes needed. The dose is essentially impossible to control because toxin content varies enormously between batches of honey. This is a poison, not a safe intoxicant. Not medical advice.
Subjective profileweighing the evidence above
This is a poison, not an intoxicant. Mad honey doses cannot be controlled because toxin content varies wildly between batches, and real exposures crash heart rate and blood pressure hard enough to need medical treatment. Nothing about it is worth pursuing.
Resources
This entry is here for reference.
Research
- 2008first citedClinical review of grayanotoxin/mad honey poisoning past and present.
- 2025most recentGrayanotoxins in Mad Honey: Mechanisms of Toxicity, Clinical Management, and Therapeutic Implic…
- 1.Grayanotoxins in Mad Honey: Mechanisms of Toxicity, Clinical Management, and Therapeutic Implications
- 2.The efficacy and toxicity of grayanoids as analgesics: A systematic review
- 3.Grayanotoxin poisoning: 'mad honey disease' and beyond.
- 4.Clinical review of grayanotoxin/mad honey poisoning past and present.
- 5.Cardiac effects of "mad honey": a case series.
- 6.Presynaptic effects of grayanotoxin III on excitatory and inhibitory nerve terminals in rat ventromedial hypothalamic neurons.
- 7.Mad honey: uses, intoxicating/poisoning effects, diagnosis, and treatment.
- 8.Mad honey (wild honey) poisoning: clinical case series from Nepal.
8 listed here; entry last updated August 2026
Reviews
My notesprivate to this device
FAQ
What is 'mad honey'?
Honey made by bees that forage on grayanotoxin-containing rhododendron flowers; eating enough of it can cause the poisoning syndrome.
Is grayanotoxin a fun high?
Not really. It is a toxin, and its effects are dominated by nausea, dizziness and a dangerous slowing of the heart rather than pleasure.
Why is dosing so unpredictable?
Toxin content varies wildly between plants and honey batches, so a spoonful that does little one time can cause serious poisoning the next.
Adverse effects
- Dangerously slow heart rate
- Low blood pressure and fainting
- Nausea, vomiting, sweating
Notes and cautions
- Heart-rhythm disturbances in serious poisoning