Since the discourse community itself is intangible, it is easier to imagine discourse communities in terms of the fora in which they operate. The hypothetical journal and email list can each be seen as an example of a forum, or a concrete, local manifestation of the operation of the discourse community.
Daily nausea can be caused by stress. An ulcer in the small intestine may cause chronic nausea. Excessive consumption of caffeine can cause nausea. A person may develop chronic nausea in relation to a peptic ulcer. Indigestion is one of the most common causes of nausea.
Frequent vomiting caused by a stomach virus can cause the body to become dehydrated, which increases the risk that bile will be included in the vomit. Patients suffering from gastroenteritis may also suffer from diarrhea, and may have trouble digesting solid food for 2-3 days. Alcohol intolerance.