Hanaoka Seishū performs the first documented surgery under general anaesthesia

Story: 1796 C.E.  |  Last updated: January 1, 1796

On a morning in October 1804 C.E., a 60-year-old woman named Kan Aiya drank a carefully prepared herbal mixture and drifted into unconsciousness. When she woke, a surgeon had removed part of her breast. She had felt nothing. The surgeon was Hanaoka Seishū, and what he accomplished that day is now recognized as the first reliably documented operation performed under general anesthesia in human history.

What the evidence shows

• General anesthesia: Hanaoka’s formula, tsūsensan, produced unconsciousness and skeletal muscle paralysis through active compounds including scopolamine, hyoscyamine, atropine, aconitine, and angelicotoxin — a pharmacologically sophisticated result by any era’s standards.
• Hanaoka Seishū: Born in 1760 C.E. in what is now Wakayama Prefecture, Hanaoka trained in both traditional Japanese medicine and Dutch-imported European surgery, synthesizing knowledge across two distinct medical traditions to develop his technique.
• Tsūsensan formula: Documented in a 1796 C.E. pamphlet by his close colleague Shutei Nakagawa, the herbal anesthetic compound took Hanaoka roughly two decades of research and experimentation to perfect — research his wife assisted with at serious personal cost.

A quest that began with an ancient Chinese surgeon

Hanaoka did not arrive at his formula in isolation. Around 1785 C.E., he learned of Hua Tuo, a Chinese surgeon from the 2nd century C.E. who had reportedly performed major operations using a general anesthetic called mafeisan — a wine-dissolved herbal powder whose name roughly translates to “boiled cannabis powder.”

Hua Tuo’s technique was, by historical accounts, remarkable. But he burned his manuscripts before his death, and the exact composition of mafeisan was lost with him. Confucian teachings of the time discouraged surgery as a violation of the body’s sanctity, and the practice died out in China after Hua Tuo’s death. What remained were tantalizing descriptions in texts written long after the fact, with no reproducible formula.

Hanaoka read those descriptions and decided to reconstruct what had been lost. His approach drew on Chinese herbal pharmacology, Dutch medical texts available through Japan’s limited contact with the outside world via Rangaku — literally “Dutch learning” — and years of methodical experimentation. His wife, whose name history has not preserved as prominently as his own, volunteered as a test subject during those years and lost her sight as a result of the trials. The human cost of his research was real.

The compound, the surgery, and what followed

By 1796 C.E., Hanaoka’s research had advanced enough that his colleague Shutei Nakagawa wrote a pamphlet — titled “Mayaku-ko,” or “narcotic powder” — describing the current state of the work. That pamphlet, though its original was later destroyed in a fire, is the first documented record of what would become tsūsensan.

The compound itself was taken as a drink. After two to four hours, patients became insensible to pain and lost consciousness. Depending on dosage, they might remain unconscious for up to 24 hours — a window that allowed surgeons to work without haste or restraint.

Kan Aiya’s mastectomy in October 1804 C.E. was the proof. Hanaoka performed a partial removal of her breast for breast cancer — a procedure that, without anesthesia, would have required the patient to be fully conscious and physically restrained. Word spread quickly. Patients traveled from across Japan to seek his care. Before his death in 1835 C.E., Hanaoka performed more than 150 operations for breast cancer alone, as well as bladder stone extractions, amputations, and tumor resections. He also trained generations of students in what became known as the Hanaoka method.

Lasting impact

The idea that surgery need not mean agony — that a patient could sleep through the knife — is one of the most significant thresholds in the history of medicine. Hanaoka’s work proved it was achievable nearly four decades before Crawford Long used ether anesthesia in Jefferson, Georgia in 1842 C.E.

His pharmacological thinking was also ahead of its time. Tsūsensan’s active compounds — scopolamine and hyoscyamine in particular — are still used today in modified forms for anesthesia support, motion sickness, and surgical premedication. Hanaoka reached those compounds through empirical plant-based research, a tradition with deep roots in both Chinese and Japanese medicine.

The Japan Society of Anesthesiologists incorporated the Korean morning glory flower — a key ingredient in tsūsensan — into their official logo as a direct tribute to Hanaoka’s work. His preserved home in Kinokawa, Wakayama, now serves as a museum and educational site, adjacent to a nursing college.

His synthesis of traditions from different cultures — Chinese herbal pharmacology and Dutch surgical technique — also models something worth recognizing. The breakthrough was not the product of a single tradition working alone. It emerged from a surgeon who read across boundaries, in a country that had deliberately closed itself to the outside world.

Blindspots and limits

Because of Japan’s national isolation policy under the Tokugawa shogunate, Hanaoka’s achievements were unknown outside Japan until after the country opened in 1854 C.E. By that time, Western scientists had independently developed ether and chloroform anesthesia, and his work had no direct influence on those developments. His wife’s contribution to the research — including the loss of her sight — was real and significant, yet she remains largely unnamed in the historical record, a reminder of how often the people closest to discovery are the least documented. Tsūsensan itself was never widely adopted beyond his school, and its exact formulations varied among his students.

Read more

For more on this story, see: Wikipedia — Hanaoka Seishū

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• The Good News for Humankind archive on modern history

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