The Cochrane Collaboration, a group of evidence-based medicine (EBM) reviewers, reviewed the use of Nei guan (Acupoint P6)  for nausea and vomiting, and found it to be effective for reducing post-operative nausea, but not vomiting, when combined with an antiemetic. However, the review acknowledged concerns about study limitations, unexplained variation in effects between studies, and an insufficient number of studies.
The Cochrane Collaboration, specialists in evidence-based medicine (EBM), analyzed the efficacy of Nei guan (Acupoint P6) for nausea and vomiting. They concluded that it was effective in managing post-operative nausea but not vomiting when used with an antiemetic. However, the review noted issues related to study limitations, inconsistencies in results across studies, and a lack of sufficient research.