A 600-year-old set of surgical tools found in a tomb in China has revealed the world's first chemical evidence of a topical anesthetic. Used to numb the skin in surgical procedures, the anesthetic was made from the highly toxic plant Chinese wolfsbane. However, the toxic plant was likely detoxified first with urine, among other things.

"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 anaesthetic medicine left on those instruments using a beam of laser light," study co-author Congcang Zhao, an archaeologist at Northwest University in China, said in a statement.