Cutting the Stone, also called The Extraction of the Stone of Madness or The Cure of Folly, is a painting by Hieronymus Bosch, displayed in the Museo del Prado in Madrid, completed around 1494 or later.

The painting depicts a surgeon, wearing a funnel hat, removing the stone of madness from a patient’s head by trepanation. An assistant, a monk bearing a tankard, stands nearby. Playing on the double-meaning of the word kei (stone or bulb), the stone appears as a flower bulb, while another flower rests on the table. A woman with a book balanced on her head looks on.

The inscription in gold-coloured Gothic script reads:

(Middle Dutch):
Meester snyt die keye ras
Myne name Is lubbert Das

(English):
Master, cut the stone out, fast.
My name is Lubbert Das.

Lubbert Das was a comical (foolish) character in Dutch literature.