paregoric vs sleeping tablet

paregoric

noun
  • A painkiller; a medicine which soothes or relieves pain; specifically the traditional patent medicine consisting of camphorated tincture of opium. 

adj
  • Assuaging or soothing pain. 

sleeping tablet

noun
  • A sleeping pill. 

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