Modern scientific techniques have been used to analyse residues of pharmaceutical substances from many ancient cultures, from Roman cosmetics and ancient Egyptian embalming ingredients to psychoactive plant preparations in the Andes. However, such residues are often less well-preserved in Chinese contexts, making it difficult to get results using the most common techniques. A recent study, published in the journal Antiquity (https://doi.org/10.15184/aqy.2026.10347) therefore applied a novel technique to investigate a pair of surgical scissors and a set of tweezers in the collection of the Jiangyin Museum, China.
The tools were discovered in 1974 during excavations of a tomb in Jiangyin County, Jiangsu Province, belonging to an individual called Xia Quan: a physician who lived 1348-1411, during the early Ming Dynasty. At this point in time, Jiangsu Province was a thriving centre of medical practice in China. Examination of these instruments therefore offered an opportunity to better understand the development of surgery in this critical period.
Researchers first used portable X-ray fluorescence to look at the elemental composition of the objects themselves. This revealed that the metal used for both had a very high iron content, reflecting purity levels that were only achievable thanks to the advanced smelting technology of the Ming period. This material was probably selected for the surgical tools because of its strength, hardness, and workability. However, it is prone to rust in humid conditions.
It was this rust that the researchers targeted, believing it to be their best chance of identifying traces of ancient medicinal substances. In adherence with Article 29 of the ‘Law of the People’s Republic of China on the Protection of Cultural Relics’, only 2mg of the red rust residue was extracted from each instrument, taken from the spots that would have been most difficult to clean, behind overlapping tongs and blades, where surgical residues were most likely to be found. The tiny size of these samples meant they did not meet the minimum requirements for gas-chromatography spectrometry, which is often used to identify such residues. So the researchers turned instead to a technique called stimulated Raman scattering (SRS) microscopic analysis. This is an advanced form of spectroscopy that involves firing two synchronised laser beams at a sample; the resulting molecular vibrations are mapped, providing detailed information about the chemical structure of the material. SRS is non destructive, fast, and versatile, and has low detection limits, making it perfect for this investigation.
The SRS analysis revealed that the rust residue contained traces of aconitine, a toxic alkaloid produced by plants of the Aconitum genus (also known as wolfsbane or monkshood), which includes Aconitum carmichaelii and Aconitum kusnezoffii. Aconite appears in Chinese oracle bone inscriptions as early as the 13th century BC. It is also referenced in a medical text from the Han Dynasty (202 BC- AD 220) and appears later in multiple lists of ingredients for ancient medicinal prescriptions. However, despite its history of medical use, aconitine can be extremely dangerous to humans. By the Ming Dynasty (AD 1368-1644), multiple methods are documented for treating the plant, including vinegar-boiling, soaking it in a black soybean decoction, and detoxifying it with mung beans. These processes resulted in a powder, known as Caowu San, which is mentioned in several written sources. Its main function was probably as a topical anaesthetic, applied to the skin to numb the area before surgery.
The traces of aconitine on the tools from Xia Quan’s tomb represent the first physical evidence for the practices documented in historical texts, indicating that this dangerous chemical was indeed being used as an anaesthetic in surgery. The researchers believe that the residue on the tweezers and scissors was probably the result of a medicinal liquid, containing the powdered aconitine, splashing on to them during surgery.
This discovery constitutes the oldest chemical evidence for a medical numbing agent currently known from anywhere in the world: it was not until the 19th century that similar practices caught on in Europe. The finding reflects the sophistication of Ming Dynasty medicine: practitioners were not only able to extract and process the toxic substance without putting themselves at risk, but had the knowledge and skills to apply it to patients in a carefully controlled manner to make surgery more manageable.
