In spite of progress made in surgical techniques and intensive care, only a slight improvement in the therapeutic control of gastric carcinoma has been achieved in the last 20 years. In this paper we present a review of controlled clinical trials on adjuvant chemotherapy and chemo-immunotherapy for gastric cancer and this topic is discussed in the light of our experience and that of the Gastrointestinal Group of the European Organization for Research and Treatment of Cancer. The results of adjuvant therapy are less satisfactory in Western countries than in Japan. The efficacy of the 5-fluorouracil + adriamycin + mitomycin C regimen in advanced gastric cancer has not been confirmed in an adjuvant setting. The therapeutic benefit reported in Japanese studies may be due to a chemotherapy started intraoperatively or during the immediate postoperative period and should also be considered in the light of a standardized surgical treatment. The new therapeutic trends, using recent chemotherapeutic associations tested in Phase I and II clinical trials or combining traditional chemotherapy with different types of immunostimulators, are discussed. Only when large-scale clinical studies have been made will it be possible to confirm their therapeutic efficacy.