folk medicine vs indigenous medicine

folk medicine

noun
  • A particular medicinal remedy used in such traditional medical practices. 

  • Traditional medical practices developed and used by non-physicians, typically involving customary homespun techniques and medicinal remedies derived from native plants. 

indigenous medicine

noun
  • Synonym of folk medicine 

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