Background: A new trend among users of new psychoactive substances’ the consumption
of “herbal highs”: plant parts containing psychoactive substances. Most of the substances extracted
from herbs, in old centuries were at the centre of religious ceremonies of ancient civilizations.
Currently, these herbal products are mainly sold by internet web sites and easily obtained since some
of them have no legal restriction.
Objective: We reviewed psychoactive effects and neuropharmacology of the most used “herbal highs”
with characterized active principles, with studies reporting mechanisms of action, pharmacological
and subjective effects, eventual secondary effects including intoxications and/or fatalities
Method: The PubMed database was searched using the following key.words: herbal highs, Argyreia
nervosa, Ipomoea violacea and Rivea corymbosa; Catha edulis; Datura stramonium; Piper
methysticum; Mitragyna speciosa.
Results: Psychoactive plants here reviewed have been known and used from ancient times, even if for
some of them limited information still exist regarding subjective and neuropharmacological effects
and consequent eventual toxicity when plants are used alone or in combination with “classical” drugs
Conclusion: Some “herbal highs” should be classified as harmful drugs since chronic administration
has been linked with addiction and cognitive impairment; for some others taking into consideration
only the recent trends of abuse, studies investigating these aspects are lacking.