antacid vs caustic soda

antacid

adj
  • Counteracting or neutralizing acidity, especially in the stomach. 

noun
  • An agent that counteracts or neutralizes acidity, especially in the stomach. 

caustic soda

noun
  • sodium hydroxide (NaOH), a strong alkaline substance used in the manufacture of paint, soap and detergents, or as a drain cleaner. 

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