Colitis refers to inflammation of the large intestine.
Also this is used to refer to inflammation of the small
intestine. Although the proper term would be ileitis
when speaking of the ileum which is the end of the small
intestine, colitis may be due to infections like
Salmonella, diseases like ulcerative colitis or Crohn's
disease.
Stress-related colitis, also called the irritable bowel
syndrome does not truly cause inflammation of the colon,
but it does cause the same symptoms.