The effect of orally administering cabbage juice on tumor necrosis factor alpha (TNF) and interleukin-1 (IL-1) productivity was studied in resident peritoneal macrophages from normal and hepatoma-bearing rats. The productivity of TNF and IL-1 was stimulated by gastric intubation of cabbage juice in the normal state, but not in the hepatoma-bearing state where the production of these cytokines had already been stimulated. From these results, cabbage may contain some effective component(s) that can be absorbed from the gastrointestinal tract to stimulate the production of TNF and IL-1.