Abstract: Provided are an intestinal barrier function enhancer capable of enhancing intestinal barrier function and thereby capable of preventing or treating metabolic syndrome, and a drug and a food or drink containing the same. An intestinal barrier function enhancer containing cells or a treated cell product of Lactobacillus crustorum. This intestinal barrier function enhancer functions effectively to enhance intestinal barrier function and to prevent or treat conditions or diseases caused by impaired intestinal barrier function such as metabolic syndrome and the like.

Abstract: The present invention provides a method for producing lactic acid bacteria having enhanced immunostimulating activities. Cultivation at a temperature that is higher than the recommended cultivation temperature of the lactic acid bacteria to be used increases the cell wall amount and the cell wall thickness. The immunoregulating activities of the lactic acid bacteria improve in correlation with such increase. The method of the present invention enhances the immunoregulating functions of lactic acid bacteria without requiring any special medium or any special process. This enhancement allows lactic acid bacteria exhibiting excellent immunoregulating activities in a human, or products including such bacteria, such as foods or drinks, medicines or cosmetics to be provided.