Abstract: The present invention relates to a prebiotic composition, a composition for improving gut microorganisms, a composition for improving gut health or gut function, a composition for alleviating, preventing, or treating inflammatory bowel disease or leaky gut syndrome, or a composition for alleviating, preventing, or treating obesity or metabolic disease, which each comprise a molokhia extract or a molokhia polymer fraction as an active ingredient to induce the proliferation of beneficial intestinal bacteria and to improve, prevent, or treat gut heath or gut function. In addition, the composition comprising a molokhia extract or a molokhia polymer fraction as an active ingredient can alleviate, prevent, or treat bowel disease or leaky gut syndrome.