Diarrhea with green watery stools is caused by acute enteritis and imbalance of intestinal flora. During acute enteritis, the smooth muscles of the intestinal wall move rapidly because of the inflammation in the intestinal system, and the contents of the intestine are expelled rapidly. Since the intestine does not have time to absorb the water, the stool that comes out is thick and contains a lot of water. The stool is acidic in nature because it stays in the intestine for a relatively short time. The stool contains a certain amount of bilirubin, which is oxidized to bilirubin in an acidic environment, so patients with acute enteritis will have green watery stools. There is a certain amount of harmful bacteria in the intestinal tract, which is normally suppressed. Once the harmful bacteria are overgrown, it will affect the intestinal function, especially when Pseudomonas aeruginosa is overgrown, it will not only cause diarrhea, but also the color of the stool will appear blue-green.