Born in Nishinoyama village, Naga district, Kii Province (now Kinokawa, Wakayama), the eldest son of the village doctor Hanaoka Naomichi. His given name was Shin and his common name Unpei. His father treated the villagers' illnesses and injuries, and Seishū is said to have grown up watching his father's work and resolved to become a doctor.
He went to Kyoto and studied the Koihō school of Chinese medicine under Yoshimasu Nangai. Koihō emphasized careful observation of real patients and treatments that actually worked. Here Seishū came to believe that medicine existed not only on paper but to save the patient in front of him.
In Kyoto he also studied Dutch-style (Caspar school) surgery under Yamato Kensui. Learning both Chinese internal medicine and Western surgery laid the foundation of Seishū's medicine, which combined the strengths of both to heal the sick. This led to his later idea of uniting internal and external medicine.
When his father Naomichi died, he returned home and took over the family medical practice. Treating many patients in the village, he was pained that some who could be saved by surgery could not be operated on because of the terrible pain, and he is said to have begun searching for a way to operate without the patient feeling pain.
Around this time, taking as his clue the story that the ancient Chinese physician Hua Tuo had put patients to sleep with a drug called mafeisan before operating, he pursued research on anesthetics. Combining herbs such as datura and aconite and testing them on animals, he spent many years examining their effectiveness and safety.
Around this time, when testing on humans became necessary, his mother Otsugi and his wife Kae are said to have volunteered to be the subjects. The tests were repeated, and in the process Kae lost her sight and his mother died (the causes are debated). Carrying his family's sacrifice in his heart, Seishū continued his research.
Using his completed anesthetic Tsūsensan, he operated on Aiya Kan, a woman suffering from breast cancer, and succeeded in removing the cancer. It is regarded as one of the earliest recorded operations in the world performed under general anesthesia, about forty years before anesthesia came into use in Europe and America.
By around this time his fame had spread across the country, and patients and students gathered from everywhere at Shunrinken, the medical school attached to his home. His students are said to have numbered over a thousand. Seishū made "unite internal and external medicine, and study the living body to grasp its principles" the pillar of his teaching.
The lord of Kishū summoned him and made him a domain physician, but he asked to keep treating patients in his village and was allowed to continue practicing at home as a rule. It is said that even after rising in status he did not change his way of facing his patients as a village doctor.
He died at Shunrinken in his home village. Besides breast cancer he performed many other operations, and his methods were spread across the country by his students. Later the devotion of his mother and wife was portrayed in the novel "The Doctor's Wife" and became widely known, and he is still remembered as the doctor who opened the history of surgery and anesthesia in Japan.
Ōtsuki GentakuRyōkanMatsudaira SadanobuKatsushika HokusaiSantō KyōdenKobayashi IssaJippensha IkkuKyokutei Bakin
People of the Edo period ・ People by period
Based on facts found in textbooks and biographies. Uncertain points are marked as such.