Abstract. The present study describes the use of bidirectional chemotherapy in the treatment of patients with gastric cancer and peritoneal carcinomatosis (PC), using newly developed response criteria for the treatment of malignant ascites. In addition, the association between effusion response and survival was analyzed. Between June 2010 and May 2014, patients affected by malignant ascites secondary to unresectable PC of gastric origin were treated with a combination of systemic and loco-regional chemotherapy. Cisplatin (75 mg/m 2 ) at an inflow temperature of 43˚C was infused intraperitoneally, and docetaxel (75 mg/m 2 ) was infused simultaneously via a peripheral vein, on day 1 every 3 weeks. The primary endpoint was overall survival rate, and the secondary endpoint was efficacy against malignant ascites using new response criteria. In total, 41 patients were enrolled, the majority of whom received 6 cycles of intraperitoneal chemotherapy in combination with hyperthermia. The majority of patients exhibited clinical regression of ascites and relief of associated symptoms. Malignant ascites disappeared [complete response (CR)] or decreased by 50% [partial response (PR)] in 73.2% of patients. No mortalities associated with the procedures occurred. The median survival time was 8.6 months, and the 1-year survival rate was 24.4%. As these new response criteria for the treatment of malignant ascites were found to be feasible, bidirectional chemotherapy may be the preferred strategy for the treatment of gastric cancer with PC. The CR, PR and non-PR groups showed significant differences in overall survival, indicating that decreased effusion was associated with improved patient survival.