Objective: The use and effect of nitrous oxide sedation techniques in oral clinics were analyzed retrospectively. Methods: Patients who were treated with nitrous oxide inhalation sedation in the clinic of the Affiliated Stomatological Hospital of Guangzhou Medical University from January 1, 2016, to December 30, 2018, were examined. Age and gender of the patients, dental treatments involved, reasons for nitrous oxide inhalation, sedative effects and adverse reactions were compiled. Results : A total of 1 429 cases were examined, comprising 587 males and 842 females, and the average age was 32.64±16.34 years old. Among the patients who underwent nitrous oxide inhalation sedation in the oral clinic, 79.98% needed tooth extraction, and 79.50% had a dental fear of procedures. The patients were divided into following 7 age groups: 5-15 years old, 16-25 years old, 26-35 years old, 36-45 years old, 46-55 years old, 56-65 years old and > 65 years old. The sedation satisfaction rate of the 5-15-year-old group was 45.71%, and the sedation satisfaction rate of the other 6 age groups was 90.83%- 96.20% (P < 0.001). The incidence of total adverse reactions was 5.39%; the incidence was higher in females than in males, and the incidence was higher in the 16-25 age group than in the other age groups (P < 0.05). The most frequent adverse reaction was vertigo (81.82%). Conclusion Among the four common oral outpatient treatment programs including the extraction of teeth, dental implants, pulp treatment and periodontal treatment, patients undergoing inhalation sedation of nitrous oxide in the dental extraction most. The most common reason for requiring sedation is dental fear, and the sedative effect of the 5-15-year-old group was significantly worse than that of the other age groups. The incidence of adverse reactions of nitrous oxide sedation was low and manageable.