The stool is very smelly mainly for the following reasons: First, the stool stays in the intestine for too long. The smell of exhaust and defecation caused by the continuous action of the stool and the bacteria in the intestine is very strong. Second, too much protein in a short period of time to eat the food. Too much protein increases the burden on the gastrointestinal tract and produces a lot of ammonia gas, including stool, resulting in a strong smell of defecation. Third, eat a lot of stimulating food. For example, onions, garlic, ginger or too sweet such as chocolate, cream, etc., including soy products can lead to defecation or exhaust very smelly such a situation. Fourth, inflammation of the intestinal tract. Especially the inflammation of the colon, the intestinal flora imbalance, the lack of probiotics and so on will lead to loose stools, there will be more smelly stools, farts also smelly situation.