More than 3,000 years ago, on the battlefield of King Wu's campaign against King Zhou, a military physician named Xiao Ai accidentally discovered a therapeutic method after suffering a burn injury. That method has continued to this day: moxibustion.

This is not a fictional myth, but a legend passed down through folk tradition and recorded in family genealogies. Today, we tell this story: the legend of Xiao Ai.

In 1046 BCE, King Wu launched his campaign against King Zhou. The army was stationed by the Qi River in midsummer, when dysentery spread widely. Half the army fell ill, with daily deaths and casualties.

The chief military physician, Xiao Ai, also contracted dysentery. He suffered severe abdominal pain and had to relieve himself more than ten times a day. Yet he refused to rest and moved from camp to camp day and night. A young doctor advised him to take a break, but he shook his head and said: "If one physician falls, dozens of soldiers may die."

One night, he dragged his weakened body across the camp. After days of heavy rain, the ground was muddy and slippery. He slipped and fell into a burning pile of wild grass used for repelling mosquitoes. His bare feet landed in the embers, and he was thrown into the fire. He was burned all over his body, with blisters forming instantly. Soldiers rushed in shock and pulled him out.

He did not know that this fall would change 3,000 years of medical history.

That night, under an oil lamp, Xiao Ai examined his injuries. The burns on his feet, calves, abdomen, and back coincidentally aligned with eight acupuncture points—Jiexi, Zusanli, Zhongwan, Tianshu, and others—all related to the spleen, stomach, and intestines. By the next morning, his dysentery had completely healed without any medication.

A bold thought emerged in his mind: could it be that the heat from the wild grass fire, transmitted through these acupuncture points, cured my illness?

He then held burning wild grass and entered the infirmary, applying heat sequentially to the same points on other patients. Soldiers panicked and fled, shouting: "Physician Xiao has gone mad!" He said nothing and treated more than twenty patients.

By the next night, all those treated had recovered and knelt outside the tent. News spread throughout the army. Soldiers began to imitate the method. Within three days, the entire army was cured of dysentery.

King Wu personally visited the camp and asked Xiao Ai about his achievement. Xiao Ai knelt and declined credit: "It is not my doing, but the fire of wild grass." The king bent down, picked up a stalk of grass, and after a moment of thought said: "This grass has no name. From today, it shall be named Ai (mugwort) after Xiao Ai. This herb shall carry your name—Ai—for generations to come." The entire army cheered.

From that moment on, this nameless wild herb had its name.

After the war, Xiao Ai did not accept court honors. He retreated to Mount Qi and spent the rest of his life studying moxibustion. Through repeated experimentation, he discovered the principles of dosage and sequence, and summarized a core rule: "Without mugwort, penetration is impossible; without correct points, there is no effect." Ordinary burning plants produce scattered heat that cannot penetrate the meridians. Only mugwort generates gentle, sustained heat capable of reaching through the channels and treating a wide range of diseases.

He compiled his life's findings into an acupuncture chart with annotations. On his deathbed, he passed it to his son, Xiao Qi, and instructed solemnly: "This is the way of saving lives. Pass it on."

This medical knowledge was later transmitted through Xiao Qi to Xiao He of the Han dynasty. Moved by the intention of saving lives, Xiao He chose not to keep it private and made it public. From then on, moxibustion spread across the land and became one of the primary external therapies in traditional Chinese medicine.

From the Huangdi Neijing, which states "what acupuncture cannot reach, moxibustion can treat," to Mencius' saying "for a seven-year illness, seek three-year-aged mugwort," and to Li Shizhen's Compendium of Materia Medica, which confirms that mugwort can treat hundreds of diseases—this fire lit 3,000 years ago has never gone out. It has become rising mugwort smoke, drifting through millennia and warming the present.

And the man who fell into the fire was named Xiao Ai.

This is the story of Xiao Ai.

An accident 3,000 years ago. A military physician falling into a fire. A night of burns and blisters. These seemingly accidental moments eventually became curling mugwort smoke that has warmed thousands of years.

The Book of Songs says: "She gathers mugwort; one day without seeing her feels like three years." Ancient people used mugwort as a symbol of longing. But what did they truly long for? Not just a plant. They longed for the person willing to walk into the wilderness to gather it; the one who used a humble body to perform acts of healing.

Mugwort may be humble, yet it can heal disease. Physicians may be ordinary, yet they can save lives.

Mugwort may be humble, yet it can heal disease. Physicians may be ordinary, yet they can save lives.

That is why the one who gathers mugwort is worthy of being missed as if three autumns had passed in a single day.

Xiao Ai was such a person. He left behind no grand military exploits, no tales of conquest. Only a stalk of wild herb, a medical tradition, and a heart devoted to saving lives.

Three thousand years have passed. The mugwort smoke has never ceased, nor has remembrance faded.

Thank you for watching Qichun's Mugwort Legacy. See you next time.