There is no specific time to use probiotics to regulate gastrointestinal flora, which varies from person to person and from disease to disease. For patients with long-term antibiotics, probiotics are taken to regulate intestinal flora, usually for 0.5 months, and for patients with long-term constipation, probiotics can be used for a long time. In the choice of probiotics, the choice varies in different cases. For long-term constipation, Lactobacillus and Bifidobacterium can be used to help constipation, and for patients with recurrent diarrhea, Bacillus subtilis and Bifidobacterium are better. The choice of probiotics should be made under the guidance of doctors. For patients with diarrhea and constipation, the causes of constipation or diarrhea need to be clarified, and after excluding organic lesions, probiotic conditioning can be carried out to regulate intestinal microecology and achieve the purpose of protecting intestinal health.