Was planning to see classmates at upcoming 20th reunion. Now I am hearing my best friend has colitis. What is that?

Colitis? Colitis, simply means inflammation of the colon. There are both chronic and acute forms. Acute forms are usually a bacterial or viral infection of the colon and can be treated with antibiotics or simply hydration, but can also be ischemic colitis involving a lack of blood flow to the colon. Ulcerative colitis and crohn's colitis are chronic forms. Surgery may be required in some situations.
Infection. It is an infection or inflammation of the colon. Can be bacterial, viral or autoimmune. First two can be contagious.