alterative vs counteragent

alterative

noun
  • A medicine or treatment which works by changing processes within the body, rather than by evacuating something etc. 

adj
  • Gradually changing, or tending to change, a morbid state into a healthy one. 

  • Causing alteration. 

counteragent

noun
  • An agent having the opposite effect; an antidote. 

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