Poire Williams is the name for eau de vie (colorless fruit brandy) made from the Williams pear (also known as Williams' bon chrétien and as the Bartlett pear in the United States and Canada). It is generally served chilled as an after-dinner drink. Some producers of Poire Williams include an entire pear inside each bottle. This is achieved by attaching the bottle to a budding pear tree so that the pear will grow inside it.
Commercial brands of Poire Williams include Williamine, produced in Switzerland by Distillerie Louis Morand and protected as an AOP.