The colon, or large intestine, is the end portion of the human digestive tract (food carrying passageway extending from the mouth to the anus).

The colon is approximately 5 feet long and 2 1/2 inches in diameter. Its major functions are to eliminate waste and to conserve water. Also, there are bacteria living in the colon which synthesize valuable nutrients such as vitamins "K" and portions of the vitamin "B" complex.