LotR -- Book 5 - Chapter 08 - The Houses of Healing

[Inziladun]

Originally Posted by Formendacil

I think the use of the terms "leech" and "leechcraft" have more to do with Tolkien evoking the ancientry of Gondor than using bloodsucking worms medicinally.

It seems you're correct.
As Théoden angrily remarked to Wormtongue in The King of the Golden Hall:

'Your leechcraft ere long would have had me walking on all fours like a beast.'

Théoden, being of part Gondorian descent, could be expected to use some of their expressions.