Drug abuse (cannabis, cocaine, opiates, and synthetic drugs) is an increasing phenomenon, especially in the younger population, thus leading to more cases of intoxication requiring evaluation in the emergency department and subsequent hospitalization. In 2017, 34.2% of students reported having used an illegal psychoactive substance in their lifetime, while 26% reported having done so over the past year. We made a review about the effectiveness of the role of the temporary observation unit in the emergency department to improve management of acute drugs intoxication. We checked medical literature from the last 10 years (2009–2019). The following electronic databases were systematically searched: MEDLINE-PubMed, Web of Science, Scopus, and the Cochrane Central Register of Controlled Trials. Then, a systematic review was carried out according to the Preferred Reporting Items for Systematic Review standards. Intoxicated patients usually display a favorable medical course, few diagnostic and therapeutic interventions, a short stay in the hospital, and, when hospitalization is needed, semi-intensive therapy is a feasible solution; therefore, intoxicated patients are ideal candidates for a temporary observation unit. The emergency department is very important to manage intoxicated patients; however, the hospitalization of these patients is often not necessary.