Nitrous oxide (N2O), also known as "laughing gas," is a colorless, nonirritating gas. Clinically, it is widely used as an inhaled anesthetic, analgesic, and anxiolytic. In recent years, recreational abuse of N2O has become increasingly common, especially among young adults and adolescents, but many of them lack awareness of the possible side effects associated with this drug. N2O abuse can damage multiple systems, especially the nervous system, but the exact mechanism of N2O toxicity remains controversial. At present, an increasing number of cases of nervous system damage caused by N2O abuse have been reported both at home and abroad. Discontinuation of N2O use and timely supplementation with vitamin B12 are essential for a good prognosis. Long-term abuse without timely treatment will eventually lead to irreversible neurological damage. In this article, we discuss the epidemiology of N2O abuse, neurotoxicity mechanisms, clinical manifestations, relevant auxiliary examinations, treatments, and prognosis to improve social awareness of N2O exposure risk, especially among users and clinicians.