Objective To apply the optimal evidence for early postoperative water intake in adult patients under general anesthesia to clinical practice, in order to provide a basis for early standardized postoperative water intake. Methods The optimal evidence for early postoperative water intake was applied using the Joanna Briggs Institute (JBI) Evidence‑Based Practice Database. A baseline survey was conducted, where anesthesia nurses and 100 anesthesia intensive care unit (AICU) patients were assessed in November 2022, in order to analyze barriers and facilitators and implement practice changes. Then, a post‑change survey was conducted, where anesthesia nurses and 100 AICU patients were assessed in January 2023. Nurses' knowledge and changes in practice compliance before and after application were compared. Patients' dry mouth/thirst degrees, oropharyngeal discomfort, satisfaction with drinking experience, nausea/vomiting, choking, and hypoxemia were compared. Results After evidence application, nurses' knowledge scores were improved (P<0.05), the compliance rates for review indicators 3, 5, 6, 7, 8, 9, 10, 11, 12, and 13 all increased (all P<0.05), the degree of dry mouth/thirst and oropharyngeal discomfort were decreased (all P<0.05), and drinking satisfaction was improved, compared with those before application (P<0.05). There was no statistical difference in the incidences of nausea/vomiting, choking, and hypoxemia after drinking (all P>0.05). Conclusions Early postoperative water intake in adults under general anesthesia improve nurses' awareness of the optimal evidence for early postoperative water intake and standardized its implementation. Meanwhile, without increasing complications such as choking, aspiration, and hypoxemia, it effectively enhanced patient comfort and satisfaction.