Peritoneal recurrence is one of the critical problems that occurs after surgery for gastrointestinal cancers. Since no curative treatment has been established for peritoneal recurrence, many efforts have been made to develop an effective method for preventing such recurrence. We focused on dextran sulfate, an anti-cell-adherence agent, to prevent peritoneal metastasis. Our previous studies in vitro and in vivo clarified that dextran sulfate prevents cancer cells from adhering to plastic flasks and the abdominal wall. In this study, we investigated the effects of dextran sulfate on cancer cells from the viewpoint of the cell cycle. Changes in gene expression caused by dextran sulfate were analyzed by cDNA microarrays. Analysis by cDNA microarray revealed the decreased expression of the genes essential to the progression of G1 and S phases. Our results indicate that dextran sulfate suppresses progression of the cell cycle as well as cell adhesion, suggesting that dextran sulfate could be used as an antimetastatic agent. Anti-cell-adherence agents with such mechanisms of action could be effective drugs for treatment during and after operation to prevent peritoneal metastases induced by surgical operation.