An incident wherein more than 30 people were poisoned with a herbal infusion during a meditation session is described. The clinical features observed were hallucinations, agression, agitation, amnesia, mydriasis, dry skin, tachycardia, hyperthermia, hypotension, collapse, coma and respiratory depression. All patients recovered, although mechanical ventilation was required in some instances. A portion of the herbal infusion was found to contain atropine (hyoscyamine), scopolamine (hyoscine), harmine, and other alkaloids. The estimated ingested doses (free bases) were atropine 4 mg, harmine 27 mg, and scopolamine 78 mg. The mean concentrations in 21 serum samples obtained approximately 6 h after ingestion of the infusion were atropine 5 ng/ml, harmine 8 ng/ml, and scopolamine 13 ng/ml.