The fire of moxibustion is "the fire of pure yang", which can supplement the "Yang Qi" of human body, make people's meridians transparent, and drive away the pathogenic yin and cold qi, thus achieving the effect of health preservation.

Modern medicine explains that the heat of moxa burning fire is a kind of far-infrared energy with the same frequency as the human body, so it can adjust the balance of physiological functions.

The ancients believed that the energy in the sky was the largest in the universe, and the sun represented the sky. People think that the sun is the master of all things, and its light, heat and energy are the cleanest and most sacred. Therefore, when our human body is sick, cold or even evil, we should transfer the magical energy of the sun to Ai, ignite Ai with such a torch, and drive away the cold or weird gas from us. That's how moxibustion came about. This fire is magical and peaceful, so Li Shizhen said in Compendium of Materia Medica: "Turn cold into peace, and then sink into well-being". Fire is warm and peaceful, especially when skyfire turns to moxa fire and then smokes. Therefore, wormwood is the earliest plant used by China people, also called kindling.