Probiotics have certain effects, used appropriately, are beneficial and cannot be called an IQ tax. Probiotics is a general term for a class of bacteria that reproduce appropriately and are beneficial to the human body. They are colonized in the human body, through the regulation of the host mucosa and systemic immune function or through the regulation of intestinal flora balance, to promote nutrient absorption, to maintain intestinal health. Currently, common probiotics include Bifidobacterium, Streptococcus, Lactobacillus, Saccharomyces boulardii, and so on. However, we should not blindly exaggerate the role of probiotics, thinking that probiotics can cure no disease and prevent no disease. In fact, probiotics are only one of the countless links in maintaining human health. Used appropriately, they can make up for the deficiencies in this link, but in excess, there are potential health risks.