lavage vs wash down

lavage

verb
  • To wash a hollow organ 

noun
  • A washing. 

  • A washing of a hollow organ. 

wash down

verb
  • To wash something completely from top to bottom. 

  • To help to swallow by drinking a liquid, after eating something, or taking a pill. 

How often have the words lavage and wash down occurred in a corpus of books? (source: Google Ngram Viewer )