alleviate vs irritate

alleviate

verb
  • To reduce or lessen the severity of a pain or difficulty . 

irritate

verb
  • To cause or induce displeasure or irritation. 

  • To induce pain in (all or part of a body or organism). 

  • To provoke impatience, anger, or displeasure in. 

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