Probiotics are a group of active microorganisms that are beneficial to the body by changing the composition of the flora in a certain part of the host, but the specific effect varies from person to person, and it is impossible to say whether it is good or bad. Probiotics commonly used in clinical practice include yeast, lactobacillus, bifidobacterium, clostridium casei, bacillus licheniformis, etc. Their preparations can promote digestion and absorption, regulate the imbalance of intestinal flora, improve immunity, and alleviate inflammatory reactions. However, it should be noted that the effect of probiotics will be affected by the selected strains of bacteria, personal constitution, drug compliance, basic health status and other factors, the specific efficacy of individual differences can exist, so it is impossible to judge the effect of probiotics good or bad. It should also be noted that the contraindications and adverse effects of probiotic preparations are not yet clear. Therefore, those who have the need to use probiotics must take medication under the guidance of a doctor, and should not blindly take medication or increase or decrease the dosage on their own, so as not to cause adverse consequences.