PURPOSE: Recent experimental studies suggest that laparoscopic surgery for abdominal malignancy may be associated with increased tumor implantation. This study investigated the influence of cytotoxic agents (administered intraperitoneally or intramuscularly) on implantation of a tumor cell suspension after laparoscopic surgery in an experimental model. METHODS: Thirty-three Dark Agouti rats underwent laparoscopy with CO₂ insufflation and instillation of a tumor cell suspension into the abdominal cavity. Rats were randomly allocated to one of the following study groups (9 rats in the control group, 6 rats in all other groups): 1) control (no intraperitoneal instillation); 2) intraperitoneal normal saline (0.9 percent); 3) intraperitoneal povidoneiodine (Betadine® to normal saline 1:10 dilution); 4) intraperitoneal methotrexate (2 doses of 0.125 mg/kg body weight in normal saline administered 24 hours apart); 5) intramuscular injection of 2 doses of 0.125 mg/kg body weight administered 24 hours apart (no intraperitoneal agent). Rats were killed 7 days after the procedure, and the peritoneal cavity and port sites were examined for the presence of tumor. RESULTS: A significant reduction in tumor implantation and port-site metastases was observed in all treatment groups (povidone-iodine and intramuscular and intraperitoneal methotrexate). CONCLUSIONS: This study suggests that tumor implantation after laparoscopic surgery and port-site metastases might be prevented by the intraperitoneal or systemic administration of cytotoxic agents. Further studies are needed to determine whether these findings can be applied to clinical practice.