The green color of folic acid stool is normal. Folic acid is not only rich in water-soluble vitamins, but also has added iron. When some people take folic acid, the iron in the drug is not completely absorbed, so there will be a large amount of iron in the stool, and the iron will react with the digestive juices to form iron sulfate in the process of digestion by the intestines, which will lead to a change in the color of the stool, and many people will have green stools. Taking folic acid will only cause the color of the stool to change, but the nature of the stool will not change. Once the stool is green in color and relatively thick in nature, you should be alert to indigestion. The bilirubin in the stool will be oxidized to bilirubin, hence the green color of the stool.