<p>The Intraperitoneal Carboplatin for Ovarian Cancer (iPocc) trial demonstrated that intraperitoneal (IP) administration of carboplatin is more effective than intravenous (IV) administration for advanced ovarian cancer, especially in cases with large residual tumors, challenging previous assumptions that IP chemotherapy is only beneficial for small residual tumors. Additionally, the iPocc trial showed that IP chemotherapy has a comparable safety profile to IV chemotherapy, with the exception of port-related toxicities. This review summarizes the principles, development, and significance of IP chemotherapy and discusses its future potential in light of recent studies. Notably, the iPocc trial, conducted under Japan’s new clinical trial regulations, achieving regulatory approval based on investigator-initiated results. The iPocc regimen offers a viable treatment option for patients with advanced ovarian cancer (stages II–IV). However, bevacizumab is recommended for later-line treatments rather than combining it with IP chemotherapy until further trials support such combinations. Future studies are needed to identify biomarkers that predict response to the iPocc regimen. The trial’s success underscores the dedication of patients and families who contributed to this groundbreaking research.</p>