alleviation vs exacerbation

alleviation

noun
  • the act of reducing pain or anything else unpleasant; easement 

  • the act of alleviating; relief or mitigation. 

exacerbation

noun
  • An increase in the severity of something (such as a disease) 

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