Fecal stones are hard substances formed after the neutralization of food and digestive juices. Most of the fecal stones are caused by improper diet, commonly due to excessive consumption of persimmons, hawthorn and other foods. Some foods contain a large amount of tannic acid and should be avoided in an empty stomach, otherwise the tannic acid will combine with the gastric acid in the digestive juices to form gastric stones. Smaller stones can be excreted along with feces, but larger stones can also lead to intestinal blockage and form intestinal obstruction. Some people drink alcohol when they eat foods rich in tannins, and alcohol and tannins can also combine to form stomach and fecal stones. Not only are fecal stones a cause of intestinal obstruction, but some people may also suffer from appendicitis due to the irritation of the appendix caused by fecal stones.