Helicobacter pylori infection is the most common cause of gastritis, gastric ulcer and adenocarcinoma. It has proven difficult to cure because of its capability to develop strains resistant to antibiotics. The effect of three strains of lactic acid bacteria (LAB) and bovine colostral preparations on the adhesion of H. pylori NCTC 11637 on gastric adenocarcinoma (AGS) cells and on the interleukin (IL)-8 production was studied. Before infection, H. pylori were pretreated with Lactobacillus plantarum MLBPL1, Lactobacillus rhamnosus GG, Lactococcus lactis, or with a colostral preparation with or without specific H. pylori antibodies. The relative number of H. pylori adhered on AGS cells was determined by urease test. IL-8 produced by the cells was studied by enzyme-linked immunosorbent assay. Colostral preparations with and without specific antibodies reduced the adhesion of H. pylori on AGS cells in a dose-dependent manner. Live LAB at a concentration of 10(10) CFU/ml reduced the adhesion by approximately 50% (P < 0.05). After the infection of AGS cells by H. pylori, the IL-8 level rose up to about 10-fold (5500 +/- 1600 pg/ml). Pretreatment of H. pylori with colostral preparations or high concentrations of LAB prevented this IL-8 rise. Similar effect was seen with live and heat-killed LAB, the live LAB being more effective. Heat-killed LAB at a concentration of 10(10) CFU/ml rose the IL-8 level of non-infected cells significantly. Suppression of IL-8 production by LAB or colostral products could have a suppressive effect on inflammation in Helicobacter infection.