Gastrointestinal has the following meanings in the field of medicine:

1. Pertaining to the stomach and intestine. The intestine is a long, tube shaped structure that is part of the digestive tract.

2. Pertaining to the organs of the digestive tract from the mouth to the anus, including the stomach and intestine.

Gastrointestinal is commonly abbreviated as GI. Gastrointestinal is also known as gastroenteric. Gastrointestinal comes from the Greek word “gaster” meaning “the belly,” and the Latin word "intestinus" meaning "inner." Put the words together and you have “the belly innner.”