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Caution :   Reactions and experiences may vary dramatically from person to person. [see below]
BZ Duration
Oral, IM, IV
Total Duration
approx. 70-80 hrs
1 hr
Coming Up
2-3 hrs
50-60 hrs
Coming Down
5-10 hrs
After Effects
10-20 hours
Hangover / Day After
days or weeks
  • upon recovery from effects, some subjects report a refreshed feeling and good mood
  • heightened deep tendon reflexes
  • clipped, flat speech
  • slurred speech
  • stereotyped utterances (fixation on short catch-phrases or figures of speech)
  • frank hallucinations, elaborate interaction with hallucinations
  • smoking and drinking of phantom cigarettes and beverages
  • decreased appetite, thirst
  • mydriasis (extreme pupilary dilation)
  • confabulation (giving plausible-but-false explanations for bizarre behavior)
  • micrographia (tiny writing, sometimes observed in schizophrenics)
  • illusion of red coloration of skin
  • loss of sense of the passage of time
  • dizziness, headache
  • errors of speech
  • dry mouth, dry eyes
  • nausea, usually without vomiting
  • subjective weakness
  • ataxia (uncoordinated movement)
  • extreme restlessness
  • clonic spasms (repetitive muscle contractions)
  • paranoia, fear, unease
  • night terrors (vivid, open-eyed hallucinations with a nightmare quality)
  • confusion, delirium, impaired cognitive function
  • sedation, stupor, semi-coma at high doses
  • perseveration (fixation on words or themes, inability to disengage from them)
  • amnesia
  • blockade of sweat glands, impairing heat-dispersal
  • cardiac failure possible in large doses
BZ is a potent anticholinergic deliriant or incapacitant. Small amounts (< 1 mg) cause long-lasting effects that closely resemble those of its tropane alkaloid cousins atropine and scopolamine, the active agents in datura and belladonna. This includes highly idiosyncratic effects such as the impulse to take off one's clothes or to smoke phantom cigarettes.

An incapacitating dose is 7-8 ug/kg (approx. 500 ug). The onset is slow, lasting roughly 3-4 hours, during which time the ingester may alternate between fatigue and restlessness, with growing disorientation. By the fourth hour, people may enter a stuporous slumber for several hours. Upon awakening, they will be profoundly disoriented for another 48 hours or so during which they will typically experience extreme confusion, hallucinations, and delirium.

BZ also has a range of physiological effects, most of which are unpleasant. These include extreme dilation of the pupil and difficulty focusing vision, which may exacerbate disorientation and hallucination. BZ also impedes heat dispersal, leading to a danger of over-heating, even in normal temperature conditions.

For a thorough and detailed description of BZ's effects, see James Ketchum's Related Resources.
Erowid's effects information is a summary of data gathered from users, research, and other resources. This information is intended to describe the range of effects people report experiencing. Effects may vary dramatically from one person to another or one experience to another based on a variety of factors such as body chemistry, age, gender, physical health, dose, form of material, etc.