Hello Thank you for trusting HCM Dear If stool passes through the intestine too quickly, there might not be enough time for bile to be digested and broken down to provide the normal brownish stool color. Normally bile is chemically changed by bacteria in the intestine to a greenish-brown color. It takes time for the bile to be fully changed in the intestine and become brown again, and if the transit time is short, for example, when a person has diarrhea, the stool remains green colored. Causes like acute gastroenteritis, IBS, Gallbladder disease, celiac disease, ulcerative colitis, crohn s disease, tumors, diverticular disease, cancers Hemorrhoids etc. It may be normal in who are taking green leafy vegetables, iron tablets, bismuth tablets consumption. I think I answered to your question if you have more questions please feel free to ask.