nepenthes vs stupefactive

nepenthes

noun
  • A Southeast Asian carnivorous plant of the genus Nepenthes; a monkey cup or tropical pitcher plant. 

  • A drug mentioned in Homer's Odyssey (c. 8th century B.C.E.) as bringing relief from anxiety or grief; hence, any drug or substance seen as bringing welcome forgetfulness or relief. 

stupefactive

adj
  • Inducing stupor; making drowsy; stupefacient. 

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