The present invention provides a method for promoting defecation, comprising administering a composition which includes: a fermentation powder of lactic acid bacteria and a physiologically acceptable excipient, diluent, or carrier. The fermentation powder includes: a fermentation product of lactic acid bacteria, the fermentation product is obtained by incubating lactic acid bacterial strains in a culture medium containing milk, milk powders, casein, soy beans, bean products, or whey, and the lactic acid bacterial strains include: a Lactobacillus salivarius subsp. salicinius AP-32 strain, a Lactobacillus plantarum LPL28 strain, a Lactobacillus acidophilus TYCA06 strain, and a Bifidobacterium longum subsp. infantis BLI-02 strain.