Gastric carcinoma occurs in response to chronic inflammation of gastric mucosa infected with Helicobacter pylori. It is not known how cytokines affect the growth and progression of gastric carcinoma. We measured tissue concentrations of the proinflammatory cytokines interleukin (IL)-1β and IL-6 in gastric carcinoma and investigated the correlation between the levels of these cytokines and clinicopathological features. Biopsy specimens of tumors or adjacent normal mucosa were obtained from 42 Japanese patients with gastric carcinoma. Tissue levels of IL-1β and IL-6 were measured by enzyme-linked immunosorbent assay. IL-1β levels were significantly higher in the neoplasm than in the corresponding normal mucosa. The IL-6 levels in the neoplasm correlated significantly with the depth of invasion and lymphatic invasion. High levels of IL-1β and IL-6 were characteristic of non-scirrhous type gastric carcinoma. These results suggest that IL-1β and IL-6 are involved in the growth and progression of human gastric carcinoma.