The aim of this study was to evaluate the impact of intradermal acupuncture (IA) at PC6 on postoperative nausea and vomiting (PONV) following cerebellopontine angle tumor resection, and to investigate possible mechanisms of action.Seventy patients scheduled for elective craniotomy were randomized into IA or sham IA (Sham) groups, with interventions applied 1 h before surgery and continued for 24 h postoperatively. Co-primary outcomes were the incidence of vomiting at 0-6 h and 6-24 h post-surgery. Secondary outcomes included the incidence of nausea and pain intensity. Electrogastrography (EGG) and heart rate variability (HRV) were used to assess gastric activity and autonomic nerve function, respectively. Untargeted metabolomic analysis of serum and cerebrospinal fluid (CSF) was also performed.The incidence of vomiting at 6-24 h (but not 0-6 h) post-surgery was significantly lower in the IA group (12.1%) compared to the Sham group (36.4%; p = 0.022). IA significantly reduced the incidence of nausea at 0-6 h (48.5% vs 78.8%; p = 0.011) but not 6-24 h. HRV analysis showed a higher HF component in the IA group post-surgery. Metabolomic analyses revealed significant changes in multiple metabolites and pathways in serum and CSF.IA stimulation at PC6 effectively reduced postoperative vomiting at 6-24 h following cerebellopontine angle tumor resection and may also reduce early nausea (at 0-6 h). The mechanisms of action underlying these effects potentially include modulation of vagus nerve activity and regulation of metabolic pathways.ChiCTR2100049992 (Chinese Clinical Trial Registry).