We report a case of intoxication by the synthetic cannabinoid MAM-2201 ([1-(5-fluoropentyl)-1H-indol-3-yl](4-methyl-1-naphthalenyl)-methanone). A 31-year-old man smoked about 300 mg of a herbal blend. He experienced an acute transient psychotic state with agitation, aggression, anxiety, and vomiting associated with a sympathomimetic syndrome. MAM-2201 was detected and quantified in a plasma sample using liquid chromatography-tandem mass spectrometry (LC–MS–MS). The level was 49 ng/ml 1 h after smoking. The use of other drugs was analytically excluded. The presence of MAM-2201 was confirmed in the herbal blend using gas chromatography–mass spectrometry (GC–MS) and LC–high resolution MS. This is the first description of an analytically confirmed intoxication and of the determination of MAM-2201 in human blood plasma.