New Research

These 600-Year-Old Chinese Surgical Instruments Are Coated in an Early Local Anesthetic—Carefully Extracted From a Poisonous Plant

Researchers say the numbing agent splashed onto iron scissors and tweezers during a procedure. They were found in a Ming dynasty doctor’s tomb

Sonja Anderson | Daily Correspondent

May 29, 2026 4:15 p.m.

Share

Copy linkEmailSMSFacebookXRedditLinkedInBlueskyPrint

Add as preferred source

In the early 15th century C.E., a doctor in China was entombed with surgical instruments. Recent analysis of residues left on those tools found that they’re coated in traces of a poisonous topical anesthetic—now the world’s earliest chemical evidence of use of a medical numbing agent, according to a study published in Antiquity.

“Six centuries ago, a Ming dynasty surgeon performed an operation with a pair of iron scissors and tweezers, and today we have read the traces of anesthetic medicine left on those instruments using a beam of laser light,” says study co-author Congcang Zhao, an archaeologist at China’s Northwest University, in a statement. “This is the first time humanity has found direct chemical evidence of anesthetics on ancient surgical tools, proving that our ancestors already knew how to safely alleviate patients’ pain with highly toxic herbs.”

Researchers discovered the instruments back in 1974, when they excavated a tomb in the Jiangsu Province belonging to Xia Quan, a physician born in 1348. Xia lived through the dawn of the Ming dynasty, which took power in China after the country’s century under Mongol rule.

According to the study, Jiangsu Province was “a thriving center for medical practice” during the Ming and following Qing dynasties. (The Xin’an Medical School—famed for its development of traditional Chinese medicine—thrived during these centuries in the neighboring province of Anhui.) However, China retains few historical records of surgical methods and tools, the researchers write.

Xia Quan’s scissors and tweezers, held at the Jiangyin Museum, presented an opportunity to find evidence of medicinal practices. The researchers first determined via X-ray fluorescence that the tools are made of iron, then they pulled tiny pieces of rusty residue from their surfaces. They hit these particles with Micro-Raman Spectroscopy.

In the residues, the researchers identified trace amounts of aconitine, a highly toxic compound found in plants of the Aconitum genus, like monkshood and wolfsbane. Historically, people used it to poison arrowheads, punish criminals and heal wounds and illnesses.

Aconitine is a frequently listed ingredient in ancient Chinese prescriptions, write the researchers. They think the residue on the scissors and tweezers indicate doctors also used the compound during surgeries. But they would have had to reduce its toxicity first. According to the study, Ming dynasty practitioners had several methods of doing so, like soaking the dangerous plant in boys’ urine, a black soybean soup or vinegar. These processes produced an anesthetic powder known as Caowu San, whose main function was to desensitize, “enabling pain-free surgery.”

Around the same era, some medieval English surgeons were also attempting to relieve patients’ pain, with sedatives like opium and hemlock. More commonly, they simply tied the awake, unlucky souls to the operating table. It wasn’t until the 1800s that Europe got its first local anesthetic: cocaine, derived from the coca plant, a new import from South America, where Indigenous peoples had long been employing its numbing properties. (Scientists later developed the safer procaine, then lidocaine.)

In 14th-century China, isolating an Aconitum plant’s toxic compound, and figuring out how to use it safely, would have required a “tremendous amount of science,” says Carney Matheson, a forensic scientist at Griffith University in Australia.

“They have to be able to get it out of the plant without harming themselves,” Matheson, who wasn’t involved in the research, tells New Scientist’s James Woodford. “Then they need to process it so it can be applied to whatever they’re going to need it for, without killing themselves or hurting people. Then they have to make sure that it actually works.”

Zhao says in the statement that the residue shows doctors like Xia Quan had the “practical ability to balance drug potency with patient safety.” Per the study, this required “precise dosing, formulated compounds and strict procedures”—and constitutes a surprising revelation about surgery in Ming China.

Matheson tells New Scientist, “Now we can understand why this surgery may have been present or may have been so prolific and actually manageable in the past.”

Sonja Anderson | Read More

Sonja Anderson is a daily correspondent for Smithsonian magazine who covers art, archaeology and culture, from newly discovered artifacts to the latest art heists.