N-methyl-5-(2 aminopropyl)benzofuran (5-MAPB) is a novel psychoactive benzofuran, created by N-methylation of 5-(2-aminopropyl)benzofuran (5-APB), which shares structural features with methylenedioxymethamphetamine (MDMA). To our knowledge, no case of 5-MAPB-related toxicity has been published in the scientific literature. We report a case of oral 5-MAPB exposure confirmed by liquid chromatography-tandem mass spectrometry in a 24-year-old previously healthy white man. Observed symptoms and signs such as paleness, cold and clammy skin, hypertension, elevated high-sensitive troponin T level, tachycardia, ECG change, diaphoresis, mild hyperthermia, mydriasis, tremor, hyperreflexia, clonus, agitation, disorientation, hallucinations, convulsions, reduced level of consciousness, and creatine kinase level elevation (305 IU/L) were compatible with undesired effects related to 5-APB or MDMA exposure. Signs and symptoms resolved substantially within 14 hours with aggressive symptomatic treatment, including sedation with benzodiazepines, external cooling, analgesia and sedation with fentanyl-propofol, and treatment with urapidil, an α-receptor-blocking agent. 5-MAPB showed first-order elimination kinetics with a half-life of 6.5 hours, comparable to the half-life of MDMA. According to the chemical structure, this case report, and users' Web reports, 5-MAPB appears to have an acute toxicity profile similar to that of 5-APB and MDMA, with marked vasoconstrictor effect.