Abuse of new psychoactive substances (NPS) and the number of patients presenting to the ER with intoxication are increasing. Treatment may at first sight seem complicated because of limited knowledge of the substance involved, but should be based on a general supportive approach recognising the relatively predictable spectrum of symptoms caused by adrenergic, serotonergic and dopaminergic stimulation. In this article, we discuss the vital elements of this approach and possible complications of NPS intoxication. This is illustrated by two 20-year-old male patients with NPS intoxication who presented to our ER as participants in a group intoxication. Patient A suffered from mild symptoms and tested positive for 4-iodo-2,5-dimethoxy-N-(2-methoxybenzyl)phenethylamine (2C-I-NBOMe) only. Patient B presented with agitated delirium and tested positive for both 2C-I-NBOMe and cocaine. While patient A was treated with benzodiazepines and rehydration, patient B required sedation, intubation and short-term ventilation.