Eight healthy participants were included in this double-blind, placebo-controlled study examining the dose-related effects of inhaled salvinorin A. Participants were administered ascending doses of salvinorin A (0.375 - 21 μg/kg) or placebo across twenty sessions with a washout period of at least one day between sessions. Placebo was administered once every five sessions for a total of four sessions, therefore participants received the treatment drug in sixteen of the twenty sessions. Physiological drug effects were measured using heart rate, blood pressure, and resting and kinetic tremors were rated on a 5-point scale. Subjective and observer ratings of drug effects were assessed using verbal participant ratings of drug strength and drug effects, and blinded observer ratings of drug effects. Participants also completed several questionnaires to assess qualitative subjective effects. Word recall and recognition was assessed using an auditory memory task. Persisting drug effects were assessed using several standardized measures of psychological function, the Persisting Effects Questionnaire, as well as ratings of mood, behaviour and attitudes from community observers. Results show that dose-related effects peaked at 2 min and then rapidly dissipated. Physiological measures were unaffected across doses. Subjective effects were intense, with maximal drug strength ratings or unresponsiveness frequently observed at high doses. Salvinorin A also produced dose-related dissociative effects and impairments in recall/recognition memory. At 1-month follow-up, there was no evidence of persisting adverse effects.