Diarrhea caused by a cold may be related to the following factors: First, the virus invades the body, causing both the respiratory system and the gastrointestinal system, so the gastrointestinal system is attacked by the virus immunity is reduced, it will produce an environment unfavorable to the existence of intestinal probiotics, stimulate the gastrointestinal tract and produce diarrhea. Second, bacteria caused by the cold, patients taking antibiotics, antibiotics will lead to imbalance in the intestinal flora will also appear diarrhea, there are some viruses such as norovirus, virus invasion of the body for the respiratory tract may appear cold symptoms, then the gastrointestinal tract will appear the entire mucosa of the gastrointestinal tract due to the impact of viruses, and serious reactions, congestion, edema, increased exudation, diarrhea performance. Therefore, diarrhea caused by cold is mainly caused by the above-mentioned reasons.