Diarrhea after taking probiotics may be normal, called Hirschsprung’s extinction reaction; or it may be abnormal, such as allergies and intestinal flora disorders caused by probiotics. Probiotics are a kind of intestinal beneficial bacteria, including Lactobacillus, Bifidobacterium, etc. Most people do not have adverse reactions after taking probiotics, at most, the stomach is a little grumbling, gas production is slightly more than usual. For some people whose intestinal flora is already dysbiotic, diarrhea, abdominal pain, fever and other symptoms may occur after taking probiotics, probably caused by the competition between probiotics and harmful bacteria, and the transient elevation of endotoxin and cytokines released during the demise of the harmful bacteria, which is called the Hirschsprung’s demise reaction. Usually within a week of taking probiotics, the intestinal flora gradually stabilizes and such symptoms disappear. Diarrhea after taking probiotics may also be abnormal, for example, a few patients are allergic to probiotics, resulting in diarrhea; it may also be a prolonged period of time to take probiotics caused by intestinal flora disorders, resulting in the occurrence of diarrhea. Probiotics should be used under the guidance of a doctor, do not take on your own.