diarrhea vs excrement

diarrhea

noun
  • The watery or very soft excrement that comes from such bowel movements. 

  • A gastrointestinal disorder characterized by frequent and very soft or watery bowel movements. 

excrement

noun
  • Human and animal solid waste excreted from the bowels; feces. 

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