<p>Postoperative nausea and vomiting (PONV) is a common surgical complication, especially in breast and gynecologic surgery, with a high incidence despite prophylactic treatment. There is uncertainty about the effective dose and therapeutic effect of drug therapy, leading to unsatisfactory results. This study aims to investigate the effect of preoperative whey protein (WP) supplementation on postoperative recovery and PONV in gynecologic tumor patients with good nutritional status, so as to optimize postoperative rehabilitation strategies. This study was a randomized, double-blind, placebo-controlled, prospective trial involving 52 patients undergoing gynecologic tumor surgery. The experimental group received WP liquid daily for 3&#xa0;days before surgery, while the R-M group received rice-milk (R-M) liquid daily. The primary endpoint was incidence of PONV and the secondary endpoints included postoperative recovery indicators such as length of hospital stay, time to first flatus and defecation, time to first ambulation, and nutritional indicators such as hemoglobin, total protein, albumin and prealbumin. Statistical analysis was performed using Python, and a <i>P</i>-value less than 0.05 was considered statistically significant. The results of the study showed that preoperative WP supplementation reduced the incidence of PONV within 24&#xa0;h after surgery, and accelerated postoperative recovery, including shorter hospital stay and early exhaust, defecation, and ambulation time (<i>P</i> &lt; 0.05). Preoperative WP supplementation reduced the incidence of PONV in the first 24 h after surgery and was associated with accelerated early postoperative recovery. This intervention may have clinical relevance in improving postoperative recovery.</p><p><i>Clinical trial registration</i>: Clinical trial registration number: ChiCTR2200059673; Clinical trial registration time: 06/05/2022.</p>