Madam Pomfrey

Poppy Pomfrey

"Pomfrey" sounds like "comfrey," a plant in the borage family that can be made into a soothing salve. Pomfrey cakes are small, sweet lozenges made from the roots of the licorice plant. Licorice also has been a medicinal ingredient for hundreds of years.

A poppy plant can be used to make opium and other drugs. It makes sense that the healer at Hogwarts would have a name related to a drug so often used for medicinal purposes.