In the last few years there has been a dramatic increase in the sale of a new category of psychoactive compounds, colloquially called “herbal highs”, “legal highs”, or “designer drugs”, which commonly display similar chemical structure and pharmacological activity to existing and illegal drugs of abuse. Among various products of this kind are so-called “spice” – herbal mixtures containing synthetic cannabinoids that bind to cannabinoid receptors and exert more powerful effects than natural cannabis. This review surveys the current state of knowledge on synthetic cannabinoids present in “spice”, their pharmacological properties and analytical methods used for their identification. It also addresses the negative consequences of using these products.