Probiotics a course is how long depends on the condition, generally ordinary acute gastrointestinal inflammation, oral probiotics for about 5-7 days can; chronic gastrointestinal disease flora imbalance, may take 1-2 months. Normal human intestinal flora is balanced, which helps a lot in the absorption of vitamins and other nutrients. The intestinal flora may be disrupted in cases such as intestinal infections. The destruction of flora caused by acute intestinal infection is temporary and can be recovered quickly. Short-term oral intake of intestinal probiotics for about 1 week can mainly play the role of inhibiting harmful bacteria, and the commonly used Saccharomyces boulardii has certain anti-inflammatory properties. Chronic intestinal diseases caused by intestinal flora disorders, need to take oral probiotics for at least 1-2 months before the normal flora can be established, need to decide the treatment cycle according to the patient’s symptoms. Healthy people intestinal flora is in a stable state, long-term application of probiotics is not recommended to avoid intestinal flora disorders.