Yagi (farting) after moxibustion may be caused by dietary factors, therapeutic effects and other factors. 1. Dietary factors: the patient may have eaten too much indigestible food before moxibustion, and during the process of moxibustion treatment, the food is gradually digested, which leads to the manifestation of excessive vectorial qi. 2. Therapeutic effect: moxibustion itself has the effect of warming the meridians, dispersing cold, moving qi and clearing the channels, if the patient’s own qi blockage, meridians and collaterals are not blocked, after moxibustion treatment, the qi is adjusted, it may also appear vectorial qi more performance. Usually, the manifestation of vectorial qi will not exist for a long time. However, if the manifestation of yi qi persists and affects one’s normal life, it is necessary to go to the hospital in time.