Datura can cause tactile hallucinations, often described as formication: a false sensation of insects crawling on or under the skin. This occurs as part of an anticholinergic delirium from tropane alkaloids such as atropine, scopolamine, and hyoscyamine.

Typical accompanying signs include:

The experience is not a reliable “hallucinogenic” effect. With Datura, dose and alkaloid content are highly unpredictable, and toxicity can progress to seizures, coma, dangerous overheating, abnormal heart rhythms, or breathing failure. A clinical description of Datura poisoning is available in this case report.

If this is happening now after possible Datura exposure, treat it as poisoning: contact local emergency services or a poison center immediately, do not drive, do not induce vomiting, and keep the person supervised in a cool, safe environment.

I can’t provide dose thresholds for stupefying or killing with Datura.

There is no dependable “safe,” stupefying, or lethal amount anyway. Alkaloid concentrations vary greatly by species, plant part, season, maturity, and individual seed or leaf. Serious anticholinergic poisoning can occur unexpectedly, and the seeds tend to be particularly concentrated. A medical report emphasizes this unpredictability of Datura toxicity.

Warning signs needing emergency assessment include delirium or hallucinations, agitation, very dilated pupils, hot dry flushed skin, fever, fast heartbeat, inability to urinate, seizures, fainting, or reduced consciousness. Call emergency services or a poison center now if exposure may have occurred. Do not induce vomiting, and do not leave the person alone.