Malnutrition has been known to affect negatively to patients` prognosis. Especially, it causes considerable side effects when the nutrition supply discontinues for a long period. It can be assumed that artificial nutrition is beneficial when the patient is in undernourished condition or malnutrition is anticipated. Enteral nutrition is widely known as reducing infectious complication by protecting intestinal mucosa. Historically, enteral nutrition existed from ancient period of Egypt, but introduced in 1910 by attempting postpyloric tube insertion, and was widely spread in 1970`s when many kinds of enteral feeding formulas were developed. However, the proving efficacy of enteral nutrition is essential due to the possibility of risks as a medical intervention and cost issues. Therefore, the principal indications of enteral nutrition should be looked into and verify its efficacy through literature review.