Activated carbon particles are taken selectively up by lymphatics when injected into the tissues and visualize regional lymph nodes colored black. Furthermore, carbon particles adsorb a large amount of the anticancer agent mitomycin C (MMC) on their surface and release the drug reversibly. Using these properties of activated carbon particles, we have applied it for lymph node dissection and chemotherapy of lymph node metastasis. After injection of carbon particles, regional lymph nodes of the stomach were found to be black; blackened lymph nodes extending widely from perigastric to para-aortic nodes were identified from other structures. Four hundred and twenty-four patients with gastric cancer were treated with this method for lymph node metastasis during 1984-1988. Involved nodes were generally colored in high incidence, about 70% of involved ones except for highly positive nodes, which was the same as noninvolved nodes. In highly positive nodes, the colored incidence was decreased to about 48%. The cumulative 5-year survival rate of the patients treated with this series was 74.6%, which was significantly higher than the figures without this method.