We evaluated the safety of paclitaxel (TXL) via intraperitoneal (i.p.) administration in 6 patients with peritoneal dissemination of gastric cancer. Four patients were treated with TXL via i.p. administration at a dosage of 80-90 mg/m2 every 1 to 2 weeks. Grade 4 leukopenia was observed in 1 patient, accompanied with massive ascites. Two other patients, who also had malignant peritoneal effusion, were treated with TXL via i.p. administration at a dosage of 60 mg/m2 every 1 to 2 weeks. All toxicities were mild in those two patients. TXL via i.p. administration at a dosage of less than 90 mg/m2 has never been reported to cause a grade 4 leukopenia. These results suggest that a phase I/II study of TXL via i.p. administration should be tried in gastric cancer patients with malignant peritoneal effusion.