Due to the nation's self-imposed isolation policy of Sakoku,[3] few foreign medical texts were permitted into Japan at that time.

He was the first surgeon in the world who used general anaesthesia in surgery and who dared to operate on cancers of the breast and oropharynx, to remove necrotic bone, and to perform amputations of the extremities in Japan.

AD 430), Hua Tuo performed surgery under general anesthesia using a formula he had developed by mixing wine with a mixture of herbal extracts he called mafeisan (麻沸散).

[5][6][7] Before the surgery, he administered an oral anesthetic potion, probably dissolved in wine, in order to induce a state of unconsciousness and partial neuromuscular blockade.

[5] The exact composition of mafeisan, similar to all of Hua Tuo's clinical knowledge, was lost when he burned his manuscripts, just before his death.

Many sinologists and scholars of traditional Chinese medicine have guessed at the composition of Hua Tuo's mafeisan powder, but the exact components still remain unclear.

"[13] Some authors believe that Hua Tuo may have discovered surgical analgesia by acupuncture, and that mafeisan either had nothing to do with or was simply an adjunct to his strategy for anesthesia.

[14] Many physicians have attempted to re-create the same formulation based on historical records but none have achieved the same clinical efficacy as Hua Tuo's.

[18] Shutei Nakagawa (1773–1850), a close friend of Hanaoka, wrote a small pamphlet entitled "Mayaku-ko" ("narcotic powder") in 1796.

[19] Once perfected, Hanaoka began to administer his new sedative drink to induce a state of consciousness equivalent to or approximating that of modern general anesthesia to his patients.

On 13 October 1804, Hanaoka performed a partial mastectomy for breast cancer on Kan Aiya, using tsūsensan as a general anesthetic.

Hanaoka went on to perform many operations using tsūsensan, including resection of malignant tumors, extraction of bladder stones, and extremity amputations.

The Japan Society of Anesthesiologists however has incorporated a representation of the Korean morning glory flower in their logo in honor of Hanaoka's pioneering work.