Also known as "broken grain", "broken grain", "broken grain", "suspended grain" and "broken grain". Taoism follows that people eat whole grains and accumulate feces in their intestines, which will produce foul smell and hinder the road to immortality. "Huang Ting Neijing" says: "The land of Cooper eats essence, evil spirits smell from the outside, and the fetish of stinking gods is zero. So, how can we get the baby back from the old place? " (1) At the same time, there are three worms (three corpses) in the human body, and they live on this grain gas. With its existence, people have evil desires and cannot become immortals. Therefore, if you want to clear the dirty gas in the intestine and get rid of the three corpse worms, you must break the valley. Therefore, Taoism imitates the immortal behavior described in "Zhuangzi Xiaoyao Tour", hoping to achieve the goal of becoming immortal.